Author Topic: Accuracy expectations with .50 cal TC BLK MTN magnum? (Read 634 times)

Larry Gibson · « **on:** December 31, 2003, 07:23:36 AM »

Thought I'd post here instead of on the modern forum. I got this rifle several years ago to hunt in Oregon with during "muzzle loader only" season. At that time Oregon required "open ignition". Since then Oregon has also outlawed the fiber optic sights, sabot bullets and requires "loose" powder only. So I have put a post front sight and TC aperture rear on the rifle. The rifle has the walnut stock and it split with the 3 pellet loads I was using with a saboted 240 gr XTP bullet. I repaired the split with Micro-Bed and also full length bedded the tang and barrel. Accuracy was 2-3 MOA with the fiber optic open sights before bedding and seemed slightly better after. I only zeroed after bedding and really did not "test" it.

I have tried RBs but they loose accuracy real quick about 15-1600 fps. I'm currently using a TC 350 gr Maxi bullet lubed with both Bore Butter and my own BP cartridge lube (doesn't seem to make any difference between the two). The Maxis cast out at .501 and just slightly engrave on the rifling when seating. I have varied the alloy from pure lead to a 1-20 tin-lead alloy with the 1-30 alloy working the best. I have tried them with and without a wonder wad and it doesn't seem to affect accuracy either. I have worked up loads with Pyrodex RS (90-150 gr) and P (90-140 gr), Clearshot (90-150 gr) and Goex FFFG (90-140 gr). All "gr" are by volume equivilent not weight.

With all but the Goex FFFG accuracy at 100 yards has been pretty dismal. I shoot a 5 shot string before cleaning. The Pyrodex and Clearshot would give 3 or 4 shots in a decent group and then 1 or 2 shots would be flyers 6-10 inches out of the group.

With Goex FFFG (and some of the last 30+ year old Dupont FFFG I have) 120 gr will put the 1st shot out of a clean barrel 4" above POA at 100 yards. The next 3 shots will cluster 2" above poit of aim with the 4 shots in 3.5 to 4". The 5th shot always goes out the bottom opening the group to 5".

Questions: Is this ok accuracy for this TC Blk Mtn Mag .50 cal with 1-28 twist or should I get better? Is anyone getting better with other bullets (remember I am stuck with an all lead bullet with no plactic wad or sabot allowed)?

Larry Gibson

Ramrod · « **Reply #1 on:** December 31, 2003, 12:02:15 PM »

Lmg,
The short answer to your question is "It should be better". Now a longer more detailed answer. I don't have any experiance with this type of gun, so take this for what it's worth, but there are some generally accepted principles working against you.
First, the 1-28 twist is pretty fast for a slug that short, that bullet was designed for MUCH slower twists.( think 1-48 and slower).
Second, the powder issue. It's pretty well known that the substitutes have a short shelf life once opened, so if your powder is a couple years old velocity will not be consistant.
Third, vertical stringing is usually a bedding issue, modern guns and blackpowder both. Full length glass bedding is not usually recommended for black powder guns, usually just the tang and the points where the barrel is held to the stock. (Under the bands on muskets, at the wedges or pins on rifles).
Just a few things to look at :wink:
Ramrod

jrkrk · « **Reply #2 on:** December 31, 2003, 06:51:13 PM »

Hey LMG try 100 grs. pyrodex select and 295gr. hollow point powerbelt bullet. I get a 1"1/2 group with mine at a 100yds. with open sights. :grin:

Larry Gibson · « **Reply #3 on:** January 02, 2004, 07:09:54 AM »

jrkrk

" LMG try 100 grs. pyrodex select and 295gr. hollow point powerbelt bullet. I get a 1"1/2 group with mine at a 100yds. with open sights. :grin:[/quote]"

If that's the "powerbelt" bullets with the plastic cup/wad at the base, they are illegal in Oregon too.

However I believe I have solved my problem. The mould I have appears to be an original TC that casts 1-30 alloy bullets out at 357 gr. I did notice the front driving band was not engraving like it should have when seating the bullet. I lapped the mould out so the front band now casts .510 and does engrave. When I "slugged the bore" with one of the new bullets the bullet came out with some really bad gouges in the rifleing grooves. A close examination of the bore showed that what I thought was a clean bore was really pretty fouled with sabot deposits. I got a .54 bronze brush and used Butches Bore Shine to get it out, took some scrubbing. Yesterday I tried the clean bore with the "new" bullets and Goex Cartridge. With 100 gr I got a 5" five shot group with evidence of keholing and bullet deformation. Dropped back to 95 gr and put 10 shots into 3.5" without cleaning between shots.

I cast 40 bullets last night with a 1-16 alloy and will try them with Cartridge and Pyrodex Select today. It takes that alloy to maintain accuracy in my BP 45-70 loads at those velocities. I'm looking for 1500-1600 fps with 5 shots into 3". If not then I won't cry about it as the 95 gr Cartridge load would have killed and deer I would have shot at and it runs right at 1400 fps. Will let you know.

Larry Gibson

mhwwlmc · « **Reply #4 on:** January 02, 2004, 09:28:24 AM »

LMG - Your Earlier Posting - "The rifle has the walnut stock and it split with the 3 pellet loads I was using with a saboted 240 gr XTP bullet. I repaired the split with Micro-Bed and also full length bedded the tang and barrel."
You ought to give Thompson Center a call. I bet they would replace that stock for free under there "Lifetime Warranty" policy. They advertised that M/Loader to be able to handle 150 Grains / 3 Pellet loads. Thompson Center is the Best in that Warranty policy they have.

Super Rat · « **Reply #5 on:** January 02, 2004, 11:16:29 AM »

I used to be a bit of a slug shooter, although I've gone the way of the roundball these days. I'll add that not all slugs shoot good lubed. My .58 slug gun does best with just the bottom lube groove of the bullet lubed, lightly. So you might try that. People tend to get stuck on the idea that a slug has to be well lubed, but that's not always what shoots best. With clean burning powders that do not foul heavily, less reason to lube heavy.

For hunting, since you are shooting from a clean barrel, you might try cleaning between shots and seeing what kind of group you get. I don't mean getting out the water bucket, but just brushing, then wiping the bore real good. Hoppe's #9+ works real good at the range. Again you don't have to get the rifle storage-clean, just clean of fouling in the bore. It's a little time consuming, but it's worth the effort. My slug gun, and my Brown Bess are both sighted in with a clean barrel, as will be the Jeager IF IT EVER GETS HERE!!!! :evil:

Being "stuck" shooting a lead slug is not a bad thing. The right slug will shoot great in your gun. Being dependent on a plastic gizmo to shoot well is worser! :roll: And as you know, a bare lead slug is bigger and heavier than some pistol bullet wrapped in plastic. That's more better. Weight is better than velocity.

I had to try several slugs in my slug gun to really find an accurate one. It turned out to be a 625 grain monster that I turned the base plug on the mould down to get a thicker skirt.
Who would have guessed? It will take VERY heavy powder charges, but I shoot it over 100 grains for a standard hunting load. Over 100 grains and the recoil becomes "severe". :oops:

1500-1600fps is not an unrealistic goal, but as you know a slug going 1300-1400fps will kill deer very well. More velocity does translate into a bit more range/flatter trajectory though. 1300fps certainly worked good for the bufflo hunters who used the .50-70, so I would not feel too much self pity using it on deer or even elk. :roll:

Hope you do already have it worked out, but those are just some other thoughts/ideas for ya.

Larry Gibson · « **Reply #6 on:** January 02, 2004, 02:47:41 PM »

Thanks for the tips guys. I met with success today.

mhwwlmc

I'd thought about contacting TC for another stock but this one now works really well and I don't mind the repair.

Super Rat

I agree with you on the lube, I only lube the bottom groove of the Maxi-Ball as it is plenty.

"For hunting, since you are shooting from a clean barrel, you might try cleaning between shots and seeing what kind of group you get."

My thought here is that when hunting I'm not going to clean between shots and 5 shots should be plenty. I may shoot and miss (I hate to admit it but I have been known to miss), reload and persue the deer. I may have hit it and then need to reload before following up. I also am prone to shoot at coyotes while hunting so I need to know where the next shots out of a fouled barrel will go. I carry four speed loaders ready plus the fixin's for another 10 shots with me.

"Being "stuck" shooting a lead slug is not a bad thing." The right slug will shoot great in your gun. Being dependent on a plastic gizmo to shoot well is worser! :roll: And as you know, a bare lead slug is bigger and heavier than some pistol bullet wrapped in plastic. That's more better. Weight is better than velocity."

No doubt about that. Back in the late '60s and early '70s Tex Shively down Oregon way got me started with muzzle loaders. All I could afford at the time was an Italian repro of a "Kentucky" in .45 cal. I used to shoot it a lot up through the mid '70s but got shooting other things. I still have the .45 and it is still deadly with RBs as I did manage to kill a couple deer and an elk with it back then.

Anyways what happened today was I stopped by the local gunshop to get some Pyrodex RS as jrkrk suggested but I ended up getting some Hodgdon's Tripple 7 FFG. At the range (it had snowed but was 37 degrees with little or no wind) I set the target up at 100 yards and was shooting from very solid benches though I was holding the rifle onle resting my hand over the front rest and my elbows on the bench. I started with 70 gr and three shots went into a nice 2" group. With 80 and 90 gr the 3 shot groups were again right at 2" but higher on the target indicating a velocity was increasing. The next 3 shots jumped to the top of the target and were in about a 4" group. I then set up the Oehler 35P and ran one shot of 100 gr over the screens, it ran 1638 fps. I then tried the 90 gr load. The five shots went into 2.25"! For a test I then fired 2 more of the 90 gr loads only without the Wonder Wad under the bullet. The first went into the middle of the group and the second went left making the 7 shot group 2.8".

The seven shots averaged 1524 fps, an ES of 28 Ffps and an SD of 10 fps. I had not cleaned the barrel (other than dry patching before the first loading) at all for the 20 shots. I carry some pre-soaked (Windex with vinigar) so I cleaned the bore using three of them and then three dry patches - it was about that simple. I then adjusted the aperture rear sight for a 100 yards POA = POI zero and fired three shots to confirm. The three shots went ing a 1.9" group at POA. I then set up a 100 yard SR1 reduced target at 50 yards to determine midrange impact. Three shots went into a very nice .75" clover leaf in the bottom half of the X ring 2.6" above POA. I was very pleased and used the remaining Maxi's over 90 gr of the 777 shooting small clumps of snow off the 100 yard berm, it was hard to miss (I didn't). Time to go hunting.

Thanks again for the tips.

Larry Gibson

Super Rat · « **Reply #7 on:** January 03, 2004, 05:11:27 AM »

All righty, sounds like you are good to go. Those are some nice groups.

On the clean barrel/fouled barrel thing I would agree that you need to know where it shoots either way. I just like to set my sights for that first shot from the clean barrel because I figure if I need a put-down shot, or finishing shot I'll be much closer and a small change of impact wont' matter. (I'll use my pistol if the animal can't get up) And actually, a four, five, or even six inch POI change won't really matter much on the side of a deer or Elk. Coyotes are a smaller target so that may be a different story.

Another thing is that if I miss something, sitting down and wiping out my barrel is not big deal, probably time to eat and drink something anyhow, and let the woods settle back down after the big boom.

It will be interesting to see how the Jaeger does in that respect. (where oh where is that big brown truck??) My smoothbore does not seem to change POI as much as a rifled bore when clean or dirty, but seems to be just as persnickity about patching, ball size, powder granulation, etc.

I plan to do a bunch of experimenting with the .58 this summer with different powders, 777, wonder wads etc. I want to see if I can get some of my lighter slugs to work as well as the 625. I have moulds for a traditional 500 grain min-yay, and one for an "improved" 500 grainer, and one for a 440 REAL bullet.