Author Topic: 6.5TCU (Read 3570 times)

DanDeMan · « **on:** January 28, 2004, 11:51:14 AM »

Dang Lucho,

You've put on your thinking cap. Or is it the prop wash from that beanie propeller:-)

I just loaded up some 6.5TCU rounds with N550 and the 140 A-Max. I was able to get 32.0 grains in. I don't know if that will be too hot, but if it is not the MV should be around 2,700 fps. I started at 29.0 grains and worked up by 1.0 grains. Tomorrow I'll be working on my flinch at the Metcalf range before the AirHead Match in the evening.

Given the light recoil for 75% of the animals loosing an extra ram or two every couple of matches is a sound tradeoff.

The 6.5TCU is certainly more efficient than the 6.5TKS. Single base rifle powders produce the same gas volume no matter the burn rate so gas pressure at bullet exit as a function of powder weight is constant.

My 6.5x08 Hunter HP ram load, 43.5 grains of N160, 139 Lapua and 2,825 fps MV, has a 64.9 (ft/s)/grain of powder efficiency ratio. As you can see it is much less efficient. Powder charge increase vs velocity increase is approximately linear over a reasonable range of pressures that we use for ram loads. There is a nonlinear increase in velocity as very high pressures are reached.

The RP cases, once fireformed should hold 30.0 grains of N150.

Later,

Dan Theodore

lucho · « **Reply #1 on:** January 28, 2004, 12:06:13 PM »

Dan

I'll be at the Air Rifle match tomorrow. We can talk then.

You still haven't explained why the TCU case is more efficient than the TKS case. Or for that matter why any case geometry is more efficient than any other case. It seems to me that only the volume of the case and the amount of powder would determine the efficiency.

By this I mean you want the least amount of powder to give you the desired velocity. And you want a case that holds just that amount of powder.

Which is what the TKS case is. (I think) But why is it less efficient that the TCU case?

Are we forgetting about barrel length?
Lucho

DanDeMan · « **Reply #2 on:** January 28, 2004, 01:22:15 PM »

Lucho,

Think about this...efficiency is a function of pressure generated for a given powder charge. If we have a case with no shoulder the primer force will maximally effect the bullet's initial movement. We want a high percentage of powder burn before the bullet moves of optimum efficiency as a function of MV vs powder charge. Also, the steeper the shoulder angle the more of the force is focused backwards and not in moving the bullet. If the primer moves the bullet too much the combustion chamber expands and therefor the pressure will be lower. A sharp shoulder angle allows less force to hit the base of the bullet and therefore allow the powder to burn more efficiently before the bullet moves. I'd love to have a 90-degree shoulder but it would collapse while sizing. Sixty degrees is probably max. Just do the force numbers as a function of angle.

Smaller case capacities are more efficient because the total volume for the expanded gas is reduced. Total volume is the sum of case capacity plus barrel volume. Simple dude, no? Smaller case capacity means that the presser is higher at bullet exit and pressure at bullet exit correlates with MV.

Dude, barrel length, case capacity, and coefficient of friction between bullet and barrel all figure into the MV equation as a function of powder charge.

Later,

Dan Theodore

JimInNJ · « **Reply #3 on:** January 29, 2004, 06:01:03 AM »

There was some excellent discussion about the TCU cartridges here a while back in a topic titled Will a 6.5 x 223 work http://www.graybeardoutdoors.com/phpbb2/viewtopic.php?t=17860&highlight=tcu+silhouette

I would like to make a few comments about efficiency verses pressure. The modern .260 can match the velocity of the larger 6.5 x 55 using less powder, so we would say it is more efficient. But the .260 operates at a pressure something like 9,000 psi higher than the 6.5 x 55.

In some rifles the little TKS has been reported to approach the performance of the .260, but those rifles have usually had their firing pins bushed to a smaller size to prevent cratering of the primers. That is a pretty good sign that the TKS is achieving its efficiency at least in part through higher pressures.

The TCU has a smaller diameter case. That should reduce hoop stress and bolt thrust, and leave more steel in the barrel shank, right? It is tempting to think it may be able to contain yet higher pressure, yielding yet greater efficiency. I dont want to be standing next to someone when they find out otherwise.

I am all for this quest for the Holly Grail of Low Recoil Silhouette Cartridges, and have had a lot of fun with the 6.5 TKS that Dan developed, but I am also a big fan of keeping my fingers and eyes and assorted other body parts attached and working. So lets be careful that in our pursuit of efficiency we do not push these little cartridges beyond their limits. Keeping pressures down extends the life of the brass, the rifle, and the shooter.

- Jim

DanDeMan · « **Reply #4 on:** January 29, 2004, 07:55:54 AM »

Jim,

Thanks for pulling up the old 6.5 x 223 thread. The issue of case capacity and case design are interesting areas for discussion. To sight some specific instances that most can relate to let's compare the 6.5 x 08 (Rem 260) to the 6.5 x 55 Swede. I've shot both extensively and done quite a bit of load development with both also. They are excellent choices for HP silhouette, but are a bit over-bore when it comes to reducing recoil and barrel erosion for HP silhouette.

Dave Imas' SAKO TRG 6.5 x 55 Swede is the rifle I purchased back in '97. It is probably the best Off-the-shelf HP Hunter rifle out there. Accuracy is excellent, great trigger when worked over properly, great cartridge feeding, 5-shot mag and great off-hand stock. The short animal load is 38.0 grains of N135 under the 107 Sierra or 108 Lapua with a generated MV of about 2,700-fps. The barrel is 23", more than enough for the light charge of relatively fast burning powder to fully accelerate the bullet. I replaced it with a Remington 260 sporting a 24" barrel, a mistake to be sure. The short animal load for the 260 was 33.5 grains of N135 with the same bullets and MV. The Swede required 4.5 more grains of powder for the same MV. The case capacity difference is minimal. A fired 6.5 x 08 case holds 55.1 grains of water and the Swede holds 58.3 grains of water. So, the 6.5 x 55 holds about 3.2 grains more water, not very much of a difference. I believe that the difference in required powder for the same MV short animal loads is also a function of case design. The Swede has more body taper with a smaller diameter shoulder. I believe that it is this greater body taper that makes the case less efficient. For comparison purposes, the 6.5TKS uses only 28.0 grains of N135 for the same MV.

After years of experimenting with optimal case capacity cartridges for Large Bore Pistol and HP Rifle Silhouette, I can say that many shooters do not pick the optimal powder for their bullet, nor the optimum bullet. Some use to fast, some use too slow of a powder. For all animals bullet BC is critical and for rams also include bullet toughness. With the smaller capacity cartridges freebore and leade angle become very important.

The current ram load for the 6.5 TCU of 29.0 grains of N150 under the 140 A-max does not produce excess pressure even though the MV is 2,520 fps. That is because the powder just about optimally matches bullet weight. I tried N140, but that powder was to fast for max MV generation. N140 is great for the short animal load with the same bullet that generates a 2,250-fps MV. The 223 case will not hold very high pressures before the primer pockets expand to the point with the case must be disposed of. The Lapua 6BR case will last many firings with my current ram loads. As a matter of fact I'm using brass that has been fired well in excess of 20 times with not one case disposed of due to enlarged primer pockets.

Regards,

Dan Theodore

Leadlauncher · « **Reply #5 on:** January 30, 2004, 12:31:20 PM »

G,day Dan

Given your thoughts on smaller capacity cases & high BC bullets, I would be very interested to hear your thoughts on where you would place the 7mm BR cartridge in the realm of rifle silhouette. Kind regards.

DanDeMan · « **Reply #6 on:** January 30, 2004, 02:45:05 PM »

G'day Mate,

The 7Br is an excellent cartridge for HP Silhouette. I'd shoot it before I'd shoot a 6.5 x 08 if it was OK for Hunter Class. If it has a 9-twist barrel, the 168 JLK with about 32 to 33 grains of VarGet, made in Auz, is super on rams. For the short animals the 139 Hornaday SBT with about 27 grains of H4895, also made Down-under, is smashing. If you've got an 8-twist use the 180 JLK with 31 to 32 grains for rams. Use the same short animal load.

Later,

Dan Theodore

nomad · « **Reply #7 on:** January 30, 2004, 07:05:52 PM »

Daniel,

As usual, you've stirred things up!
Glad to see that you're on board.

Q: What do you mean: "if it was OK for hunter class." ? Didn't Rem offer both rifles and ammo for a short time? Am I out of the loop again? :eek

DanDeMan · « **Reply #8 on:** January 30, 2004, 09:23:21 PM »

Ernie,

I was wondering who would rise to the 7BR bait:-) An 8 or 9-twist, 26" barrel would make a dandy HP Hunter rifle. It's too bad nobody makes a high BC 140-grain bullet though.

Later,

Dan Theodore

nomad · « **Reply #9 on:** January 31, 2004, 05:16:56 AM »

"Rise to the bait"? And I thought were were friends. :cry:

You going to SHOT? I want to talk there with the fellow who's developing the 6.5 Grendel -- which looks superficially an awful lot like that 6.5 TKS thingy that some granola types out on the left coast dreamed up... :-D
(I'll assume that you're familiar but, just in case, the Grendel is/is supposed to become a 'factory' round with Lapua brass and production rifles. One of the other posters on here already mentioned it.)

lucho · « **Reply #10 on:** January 31, 2004, 05:17:06 AM »

I thought a company had to produce a caliber in a factory rifle before it could be used in the Hunter Class. So I didn't think a 7BR would meet the rules.

How about the new Winchester Short Mag (WSM) or one of the other new short mag's in 7mm?

Lucho

nomad · « **Reply #11 on:** January 31, 2004, 05:20:16 AM »

Lucho,

'Magnums' ain't allowed...

JimInNJ · « **Reply #12 on:** January 31, 2004, 07:47:34 AM »

Dan, it looks like you have become a fan of the A-Max. I thought your testing had favored more heavily constructed bullets such as Lapua or Carterucio.

It also looks like you are moving toward heavier bullets at lower velocity. Makes since to me, as it is momentum that knocks over targets. I have always wondered how far one could go with this. 155gr bullets in the TCU? How about some 250 or 300gr VLDs in a .338-221? :wink:

- Jim

DanDeMan · « **Reply #13 on:** January 31, 2004, 07:50:51 AM »

Ernie,

Hey, if you can't throw a friend some "red" meat to chew on, who can you?

Won't be heading over to the SHOT as the AZ Creedmoor Championships is happening at the Ben Avery during the same time frame. You know, single-shot's with that nasty black stuff and iron sights at 800, 900 & 1,000 yards. Like they say, "Once you've gone black, you'll never go back!"

The 6.5 Grendel should make a dandy HP Hunter round. Designing the front end of the reamer is the key to getting a small capacity case like that to work well. There is no reason that one shouldn't be able to generate 2,650 to 2,700 fps with a 140 VLD as long as one has a properly built rifle and knows how to tweak the load for optimum performance.

I've done a bit or research on the 6.5 Grendel. Looks like the Over-the-course guys are looking to drop that puppy into an AR-15. I don't know what the max cartridge OAL is for the AR-15, but I suspect that the reamer will have to be designed so that the long bullets, which is where the cartridge will shine, will need to be well into the case. I'm thinking that the straight 6PPC would be better as the 6mm 107 Sierra works very well at 600 yards for paper punching.

Later,

Dan Theodore

DanDeMan · « **Reply #14 on:** January 31, 2004, 09:55:23 AM »

Jim,

The only reason I'm using the 6.5 A-Max is because at the time of deciding to play with the 6.5TCU I found 2K A-Maxs for $280. The best commercial 6.5 ram bullet is still the 139 Lapua Scenar as it was the toughest (compressive strength, not Brinell Hardness) 140-grain class 6.5 VLD out there the last time an extensive test was performed using my pendulum bullet smasher. Carterucio also makes a very tough 140 VLD that has a thick jacket and tiny meplat. His thick jacket VLD is a bit tougher than the Lapua and has a bit higher BC. Bobs big, bad bullets are very accurate, the most accurate heavy 6.5s Ive ever shot. My 6.5TKS ram load has produced 5-shot; 3/4 groups at the ram line on paper and 0.12 groups at the chicken line.

Too many years focused on BPCR's has got my mind rapped around, Heavy and slow is the way to go. I'm currently shooting a 365-grain 35-40 Maynard bullet at 1,190 fps. Now that is heavy and slow:-)

Years ago I used a 30-221 in an 8-twist, 15" barrel XP-100 for pistol silhouette. That puppy had no recoil or report. Only 7.5 grains of SR4756 launched a 200-grain MK to 1,100-fps. The problem with going that slow is that the trajectory is about 60 MOA from firing line to ram-line for HP Silhouette, not practical. Also, velocity induced vertical dispersion is a real problem. For instance, with a 6.5 TKS launching a 141 Carterucio at 2,775-fps, the random vertical dispersion that results from a velocity extreme spread of say 25-fps is only 1.6" of velocity variation induced vertical dispersion. But, if we use the 30-221 at 1,100-fps with the 200-grain MK the random vertical dispersion at the ram line that we can't control for is a whopping 16.9". The belly to back distance on a ram is about 13".

A 7BR loaded to 2,400-fps and the 168 JLK that has a 25-fps velocity extreme spread generates about 2.5" of random vertical dispersion. If one fine-tunes their ram load so that the low velocity exits the barrel just before one of the two max modes of barrel vibration they will be able to "flatten the longrange random vertical dispersion. In BPCR longrange load development that is very important as velocity variation induced vertical dispersion can put you well back in the pack at a big match.

So, heavy and slow has its limits. One of the reasons that BPCR's can shoot heavy and slow well is because it is possible to reduce velocity extreme spread down to single digits.

Later,

Dan Theodore

nomad · « **Reply #15 on:** January 31, 2004, 03:40:41 PM »

Lucho,

Apologies -- I think we bypassed your post somewhat.
AFAIK, the 7BR was produced as a factory offering for a short time (very short) and that makes it legal for hunter. I have to admit that I've never seen one and, if I were going to build one, I'd contact Rem and get the production period...
I doubt that there will be any effort to change the 'no magnums' rule in order to accommodate the new short offerings but who knows?

lucho · « **Reply #16 on:** January 31, 2004, 05:39:37 PM »

Guys

I thing the WSM's are not belted. And you don't have to load them to Magnum speeds.

I thought they would be best because of their shorter cases.

Does just having the word "magnum" in the name make it illegal?

Lucho

nomad · « **Reply #17 on:** February 01, 2004, 05:45:57 AM »

Lucho,

3.1.1 (a) Caliber: 6mm or larger, provided that wildcat belted magnums are not allowed.

Amusing: If you read the rule literally (and make no allowance for the fact that someone apparently skipped a whole BUNCH of English classes) you can use any magnum, belted or otherwise, that isn't a 'wildcat'. OR any wildcat that isn't either belted or a magnum, etc, etc. If'n it doan hit on em all, tain't perhibited! Gotcher 6.5/.50 BMG Ackley Improved reddy fer the cummin nashunnals?

I'll take a wild one here and guess that they meant to say that 'wildcat, belted and magnum cartridges are not allowed' and that an AI BMG won't pass tech at most matches...and if it does, they'll DQ it after the first ram vanishes over the horizon! :-D

Leadlauncher · « **Reply #18 on:** February 02, 2004, 11:36:03 PM »

G,DAY AGAIN DAN & FELLOW LEADLAUNCHERS

BEING 55 WITH CHALKY BONES I ALSO AM IN THAT SEARCH FOR THE HOLY GRAIL OF LOW RECOIL AND ONE RAGGED HOLE AT 500 METRES. GIVEN YOUR RECENT EXPERIMENTS, HOW DO YOU FEEL ABOUT THE 7MM BR NECKED DOWN TO 6.5MM?.

KIND REGARDS

Arizona Jake · « **Reply #19 on:** February 03, 2004, 02:16:29 AM »

Leadlauncher:

Please follow the discussion "BR or IHMSA" on this forum. There are a few points of view which may give you some answers, G'Day, :cb2:

DanDeMan · « **Reply #20 on:** February 03, 2004, 06:41:19 AM »

Leadlauncher,

The 7BR necked down to 6.5 will work great as a low recoiling HP Silhouette rifle cartridge. There are, however, several caveats:

1. Must use 6mmBR Lapua brass opened up to 6.5mm
2. Must have reamer designed so that 140-class VLDs seat so at most only the BT is below the neck-shoulder junction.
3. Firing pin hole should be smaller than 65/1000ths to reduce primer blanking (little disk that can be punched out of the middle of the primer from too large of a firing pin hole like Remingtons). These small, relatively large diameter cases cause blanking even though the pressure is not that high. I believe it is the result of the combustion dynamic generated with such a low aspect ratio case. The pressure on the fired primer is high enough to press the middle through the firing pin hole producing the little hole in the middle of the primer and a little disk in your bolt or that sometimes drops into they recoil lug area of your action . By reducing the typical Remington firing pin hole of about 80/1000 ths down to say 65/1000 ths the force goes down by the square of the diameter, but the cutting circumference of the hole only goes down by the diameter. That is why smaller diameter firing pin holes are less likely to blank primers. For instance an 80/1000ths firing pin hole has a surface area of 0.0050 square inches and a diameter of 0.2513. A 65/1000ths firing pin hole has a surface area of 0.0033 square inches and a diameter of 0.2042. It is the chamber pressure on the unsupported primer center over the firing pin hole that causes it to blank. When the firing pin hole diameter is reduced from 80/1000 down to 65/1000 we see that the pressure on the unsupported center of the larger firing pin hole is about 52% higher than the smaller diameter hole, while the diameter or cutting edge of the firing pin hole is only increased by 23% for the larger diameter firing pin hole.

The following are recommended for minimizing felt recoil and making the small cartridges work:
1. Chamber freebore at bullet diameter, 0.2640", not larger as a tight freebore is necessary to insure that the 107's and 108's shoot well. One of the reasons that quite a few 6.5x08 HP rifles don't shoot the 107's and 108's well is for precisely that reason.
2. Best powder for 140 VLD ram bullets is N150. H4350SC is TOO slow. If you use moly-coated bullets then VarGet, RL15 and N140 will all give good performance. They all work the same in the 6.5BR and 6.5TKS.
3. Good pwder choice for 107 or 108's is N133 or similar burnrate powder
4. Use Remington 7 1/2 primers for your ram loads as they are the toughest primers and less prone to blanking if you do not reduce the firing pin hole diameter.
5. Use at least a 26" barrel. A 28" is better. The longer the barrel the less the felt recoil
6. Put an 8-oz mercury recoil suppresser in the butt stock with one end up against a Pacmyer Decelerator recoil pad. Make sure the mercury recoil suppresser is in line with bore.
7. Stock design and construction material effect felt recoil. Probably the best recoiling absorbing stock out there is the Neseka Bay stock made in Canada.
8. Have LOTSA fun slamming steel.

All the best,

Dan Theodore

DanDeMan · « **Reply #21 on:** February 06, 2004, 04:19:33 PM »

Good Evening,

A few days ago N550 was experimented with to determine how fast the 140 A-max bullet could be pushed out the muzzle with the6.5TCU. The accuracy was so poor that MV is of no consequence. The 140 was pushed to 2,680 fps, but who cares when accuracy is 2 MOA.

The current ram load of 29.0 grains of N150 is still looking good at 2,520 fps and 1/4 MOA accuracy. The round will be tested with 29.5 and 30.0 grains of N150 next week.

The C, P & T load is still 26.0 grains of N140 under the 140 A-max at MV of 2,250 fps with 1/4 MOA accuracy and better wind deflection then a 107 Sierra at 2,700-fps with less felt recoil.

Regards,

Dan Theodore

dave imas · « **Reply #22 on:** February 07, 2004, 05:58:28 PM »

okay... now tell me again uncle dan... why in the name of all that is holy are you shooting 140's for your short animals? beyond the fact that you are a big strong burly man that enjoys a bit of pain with his morning coffee.

dave imas · « **Reply #23 on:** February 07, 2004, 06:11:06 PM »

and another question for those of us that went to school on the short bus... a bit off topic but all the usual suspects seem to be attending this thread so please excuse the liberty...

now that we are able to take any action, attach any trigger (2lbs), plunk on any barrel (tapered), and slop it in any stock (hunter config), why is it that we care what cartridge it might be?
why is it that we (the royal we) have decided that it matters that a remington action must be chambered in a cartridge that remington saw fit to provide to the public... at one time or another, for perhaps a run of 50, during the last millenia. i know i am an uncaring sort of fellow and perhaps i should begin to care about something and perhaps this particular subject might be a good place to start... but!!!! if you have a remington action with a schneider barrel, a jewell trigger, and a nesika bay stock i lose the notion of relevance regarding anything remington might have done as it relates to this particular rifle.

your honor, please insist the witness answer the question!

nomad · « **Reply #24 on:** February 07, 2004, 08:53:01 PM »

David,

As 'We' have heard it from people who have cousins who know people who've met someone who heard the name of a person on the silhouette committe who supposedly actually shoots an ocassional match, the word from THE COMMITTEE is: "'Cause We're the daddy! That's why!"

Apparently, once the stone tablets engraved with THE COMMITTEE'S paternal directives are brought down from Sodom-on-Potomac, no more rational explanation is required. Those of us lowly types who regularly inhabit the ranges during matches are expected to render unquestioning obedience to the god-like beings who govern us from that sacred place! :roll:

(Why else would we still face the "Load magazines after the ready command." rule when more than 3/4 of the attendees at the competitors' meeting two years ago in Raton voted to remove it? The caliber rule, by comparison, pales...)

DanDeMan · « **Reply #25 on:** February 08, 2004, 08:11:34 AM »

Yo Imas,

What a great straight-man you are. Remember Uncle Dan's mantra, "Ya gota shoot the BC's." As you well know, we want the following in order of importance for HP silhouette:

1. Low recoil
2. Low wind deflection
3. Accuracy
4. Reduced barrel heating that can effect the accuracy of the second string of fire in hot conditions.
5. Low barrel erosion

The first 2 are what we need to design for because we should expect number 3, accuracy, and 4 and 5 we can workout without too much effort.

So, # 1, low recoil for both ram and short animal loads. The best way to do that is to use the highest BC bullet we can find that will shoot accurately in our rifle. Along with that statement goes the question of which bullet for the short animals. With that in mind lets do the numbers with the 107 Sierra and 140 A-max for the short animal load. First well look at the numbers for a typical 107 Sierra MK at 2,750 fps out of a 10-lb rifle.

107 Sierra MK at 2,750 fps:
Recoil: 6.8 ft-lbs
Wind Deflection from 10-MPH crosswind at turkey line: 15.9

140 A-max at 2,250 fps:
Recoil: 6.2 ft-lbs
Wind Deflection from a 10-MPH crosswind at turkey line: 13.8

As you can see the recoil AND wind deflection are lower with the 140 A-max load. Also, it should be noted that the difference between the felt recoils is much greater as the currently used recoil equations do not capture two substantial parameters effects on felt recoil that are in favor of the 140 A-max load.

Later,

Dan Theodore

Metalhead · « **Reply #26 on:** February 08, 2004, 03:04:26 PM »

Hi Dan / PelletHead...your gonna love this...Dave gave a shooting clinic at Tacoma Sportsman's Club on Saturday...$30.00 a pop....Now I went up there today for the registered Sunday smallbore match a perfomed just terribly..as usual...But..as I was standing off to the side, Dave was saying to a bunch of smallbore shooters who were asking questions about the highpower game...that if your .260 / 6.5 x 55 High power C-P-T laod did not feel like an air rifle at the shot...then you have got it wrong....

Believe it or not...I kept my mouth shut....but really...a 6.5mm

C-P-T load feel like an air rifle...c'mon..gimme a break....

but...every person is entitled to his or her opinion..right?

davei · « **Reply #27 on:** February 09, 2004, 08:04:09 PM »

Thanks Dan,
i didn't even think about slowing the bullet down to the 2250. i still had the 2550 velocity in mind. makes sense. 2250 puts it into a tcu kinda range.

metalhead. clearly a centerfire rifle isn't going to feel like an air rifle. the point was that one of the shooters was actually uncomfortable shooting his short animal load. he felt little difference between his short animal load and his ram load. from that point of reference, an effective chicken load could feel wonderful when compared to a ram load. no pain shooting and, hopefully, better performance. my sincerest apologies to you for exaggerating the point. too bad we didn't talk about it at the time.

dave

haroldclark · « **Reply #28 on:** February 16, 2004, 09:58:49 AM »

In the mid 1970s I ran a series of tests on handgun ammunition for the Alameda County Sheriff's Department. One of the things that came out of the tests that I wasn't looking for was an unexpected recoil factor. Of course, I was testing for recoil related in foot-pounds of energy (pain) and I was measuring the travel of the gun on a comparison basis.

Story is: I used a S&W Model 66 4" stainless 357 Magnum strapped in a Ransom Rest that was mounted solidly on a steel system. The gun was fired in Total Darkness and photographed to determine the cylinder gap flash and muzzle flash. This is essential info for night gun fights. The ammo that was arbitrarily selected by the training division caused a flash that blinded the shooter.

The Ransom Rest allows the firearm to react to the recoil and move straight up and back to 45 degrees of travel.

Finding: The firearm, in all cases of firing, did not start to move from recoil before the bullet, muzzle flash and barrel to cylinder gap flash transpired. Over 100 photographs were taken and in not one incident did the firearm move.

This was contrary to my prior belief. I believed that the moment the bullet started to move forward, there had to be recoil movement to the rear. That fit into my understanding of the laws of physics. For every action, there is an equal reaction. Apparently, the extreme fast movement of the bullet against the heavier weight of the firearm allows the bullet to exit (being that the bullet is lighter) before the firearm can react. Another belief that I have formed is that the fast moving hot gases escaping from confinement is the real cause of the recoil, thereby pushing the firearm away in recoil.

That is a fact in my findings.

Harold W. Clark

DanDeMan · « **Reply #29 on:** February 16, 2004, 11:55:06 AM »

Harold,

You findings track with my experimental evidence. My research and experimentation suggest that most of the "felt recoil" that causes flinching and poor follow-through is from the rocket effect of the hot gasses exiting the muzzle. So, when we integrate your findings, that support my assertions, we find that high BC bullets launched slowly with small charges of powder to drive down recoil and wind deflection at the same time is the way to go to improve HP silhouette performance from an equipment design perspective.

Regards,

Dan Theodore