Author Topic: Vertical groups, help. (Read 980 times)

MOGLEY · « **on:** April 12, 2007, 12:21:47 AM »

I have been load testing for my 204 ruger bull barrel. I have seen significant difference in loads but have noticed one constant in all groups. They are vertical. first shot is usually high and then the next for work there way down. I may have a 3 1/4 group but only 1 1/2 wide. The first shot being the culprit for the large group. the rest are usually not more than 1/2 in apart. I cannot seem to do better than 1 1/2" grouping. Is this a sign of something needed to be done to the forend?. If there was a diagonal l string, I know it would be the forend hitting on one side.I read about the forend screw needing to be tightened a certain amount.......... Thought I would ask first and try to avoid some frustration. I have never messed with a forend where the barrel depends on it to stay mounted. Can I file away the wood from the barrel and just depend on the surface area of the screw and post to keep the barrel where it should be? Thanks for the help.

Slowhanddd · « **Reply #1 on:** April 12, 2007, 12:39:31 AM »

I would try the oring trick.That's putting a oring over the barrel bolt and tighten the screw snug.Also try shooting it with out the fore arm on it.That will tell you if it's the problem.Another thing where are you resting the forearm on the bag will make some difference.I also notice I need to close the gun up just about the same every time.Dave

Fred M · « **Reply #2 on:** April 12, 2007, 03:08:11 AM »

Verical stringing could have several reasons. That is inconsistant lock up caused by
a weak latch spring plus a gap beween the standing breech and the barrel.

A loose connection beween the forearm and the action. A o-ring wont help with a loose joint.

Tighten the forearm hinge joint and bed it full length with uplift pressure on the tip.

See my accurizing method in the FAQ.

cjg_beef · « **Reply #3 on:** April 12, 2007, 04:58:28 AM »

From what I've heard vertical stringing can also be an indication that you need to use more powder.

quickdtoo · « **Reply #4 on:** April 12, 2007, 05:17:27 AM »

Please read the Handi Basics 101 sticky, point #5 has your answer about the forend.

Tim

John Boy · « **Reply #5 on:** April 12, 2007, 09:55:25 AM »

Mogley ... there could be a lot of reasons:

http://www.cci-ammunition.com/default.asp?menu=1&s1=6&s2=15&pg=1
# Stringing of shots (where the bullet holes are in a line instead of a symmetrical cluster) can be a gun problem. However, the first thing to check is your shooting position. Barrel touching the rest? That will often cause vertical stringing. If you adjust your position and still get vertical stringing with most ammo types, you may have a loose stock (see 3 above). Horizontal stringing can be caused by a stock fit problem, jerking the trigger, or it could be crosswinds. If the latter, wait for the wind to die down. Sighting should be done with no crosswinds whenever possible. If you try to correct for a 20 mph wind at the range on Tuesday, you'll be all over the place when you get to the hunt on Saturday.
# In revolvers, the barrel/cylinder gap must be no larger that 0.012 inch. An excessive gap can cause vertical stringing due to velocity variation and, worse, could cause a dangerous bullet-in-bore condition.

http://www.6mmbr.com/verticaltips.html

http://www.shootingsoftware.com/measure.htm
(Vertical & Horizontal Spread) The Horizontal and Vertical Spread of a group is simply the greatest distance between shots on the vertical or horizontal plane. This contrasts with the Maximum Spread which can be at any angle across the group. This measurement is understood by most shooters, easy to make, and can be used to help detect load and mechanical problems or "pulling" by the shooter. If the Vertical or Horizontal Spread is significantly larger and shots are well dispersed, it is called "stringing". A cross wind will obviously disperse shots horizontally. Vertical stringing may be caused by irregular powder charges and detonation problems (inconsistent ignition due to variations in primer pocket depth or primer thickness). Improper crimping, bullet inconsistencies or other loading problems usually result in larger overall group sizes, and not "stringing" in any particular direction. A loose gun sight, or broken scope may also cause stringing.

MOGLEY · « **Reply #6 on:** April 12, 2007, 11:46:46 AM »

tonite I removed the forend to shoot 4 shots. Same thing! here is a pic

This is exactly what I am encountering. first shot is the highest and progressively gets lower with each shot. Talk about hard to adjust the scope! I ahve not checked headspace clearance as yet. It LOOKS tight. I want to emphasize each shot is smooth, benchrested on sand bags and looks and feels as it should when the gun fires. I do not pull the trigger and do not apply pressure down on the gun. I rest in on the hinge and tonite i was back from the hinge so the barrel did not touch anything. Lock up is consistant. Bullets are as exact as one can get for bullets and powder charges. In this case 29.5 grains of varget. Ther is no room left in the case for anymore powder. These averaged 3875 fps for speed.....

Spanky · « **Reply #7 on:** April 12, 2007, 12:14:51 PM »

I had the same problem with my 30-06 barrel when sighting in. My problem was the scope. I replaced the cheap Tasco with an old Weaver 4x and the problem was solved instantly. I'm not saying that's your problem but it wouldn't hurt to check it out.

Spanky

djw · « **Reply #8 on:** April 13, 2007, 02:26:30 AM »

Mogley,

How long are you waiting between shots?

What happens if you fire more than 5 shots? Does the vertical stringing start reducing?

Don

Dave Allen · « **Reply #9 on:** April 13, 2007, 03:56:38 AM »

mogley...i assume you started below 29.5 grain's...how did it shoot with a lower powder charge ??

edgemark · « **Reply #10 on:** April 13, 2007, 04:36:52 AM »

Quote from: Dave Allen on April 13, 2007, 03:56:38 AM

mogley...i assume you started below 29.5 grain's...how did it shoot with a lower powder charge ??

+1

You also wrote that the velocity AVERAGED 3875 fps, what were the actual numbers for this group?
Personally I would either swab the bore between each shot to see if this is a fouling issue, or I would drop 10% in my load to see if that made a difference in the group.

edge.

McLernon · « **Reply #11 on:** April 13, 2007, 10:22:02 AM »

Yep, latch engagement and tightness of the standing breach. Assuming you checked the standing breach gap and it's O.K. then latch engagement must be the culprit. Note that the engagement should be such that it is about 1/16 right across the lug shelf.

Mc

MOGLEY · « **Reply #12 on:** April 13, 2007, 11:33:21 AM »

Lets see as far as loads. I have been working on many different loads with different powders, 322 3031 varget 4198 etc all with mild tohot loads. When I say it shoots x fps, It is the average of a 5 shot group. The spread of vertical changes with mild and hot loads but the vertical is a constant.
I put a piece of regular copier paper in the action and close it up..( don't laugh, I cannot find my feeler guages) and it really holds on I cannot move it at all when closed I would say it is very close tolerance.
I do have a Tasco on it. I was just given a leopold to use and am going to swap it out tonite and then shoot the cr-p out of this thing tomorrow. I have not had much luck with scopes and they have been on really heavy recoiling guns like a 17 hmr, 17 mach 2 and a 222! I would think if any scope would hold up it would be on those guns. I swear anything below 200.00 dollars is not worth messing with. I do not mind telling you I am not made of money and so far I have not invested more than 165.00 in a scope. Seems like everyone else has more luck than me in this area.

I have a bull barrel on this gun and it barely gets warm when shooting. I do not shoot fast with it. Probably a shot every 1 1/2 minutes for the 5 shot group.

quickdtoo · « **Reply #13 on:** April 13, 2007, 01:03:24 PM »

Smoke the latch shelf and see how the engagement actually is, it can be very telling. I've had some factory fitted barrels that were hitting very heavy on one side and not at all of the other side, easily fixed with a little honing. That's all covered in the barrel fitting info in the FAQs. Even if you just lightly hone it to smooth it, it can help improve consistency in latch engagement.

Tim

http://www.gboreloaded.com/forums/index.php/topic,82412.msg504758.html#msg504758

Fred M · « **Reply #14 on:** April 13, 2007, 02:54:47 PM »

MOGLEY.
To start with you have a 0.004" to 0.0045" gap if you can close the action on a copy paper sheet.

Since you neck size only you have no control of the shoulder to to base dimension.
Neck sizing in Handi with its springy action will give you various shoulder to base
dimensions, hence various amount of latch engagement. That spells vertical stringing. Add to that the expansion of the barrel and action the rifle will progressivly shoot lower with each shot as it warms up.

All cases must have the same shoulder to base dimension. Nothing can stick out past the the face of the barrel. Primer must be 0.002" below the case head.

That means you FL die needs to be set up to set the shoulder back until the
base of the case is flush or no more than 0.002 below the barrel face.

You for sure get rid of the gap, and forget about neck sizing only. Hand loading
for a Handi is not excactly the same as for a bolt gun.

MOGLEY · « **Reply #15 on:** April 13, 2007, 04:35:18 PM »

Wow, I had no idea things are that precise. and... I can tellyou I do in fact have various fittings rounds. Some slidein like they should while others have to be forced in for everything to fit right. I thought it was the shoulder of the case. Yousee, sometimes the bullet does not go right into the case easily and the bit of fetching it does alters the shoulder where it meets the wider part of the case. Not bad but you see it. This makes it a bit difficult to close and there by confirms your explanation of what is happening. I think.
I have rcbs dies for the 204 It "full length" sizes I think but does not actually go right to the base or at least indicated by the wear signs of the die. Whats next?? different dies? Mine are adjusted right to he shellholder. As I mentioned before, the decapper die does not expand the neck case to help accept the bullet either. I thought RCBS dies were about the best. I guess I need an education here as well.

Fred M · « **Reply #16 on:** April 13, 2007, 05:10:45 PM »

MOGLEY

Some presses have a lot of spring in them and may not let the shell holder fully close on the die. It is important that each case has to be the same when the shell holder is tight against the bottom of the case.

If your cases are not flush with the barrel face you may have to reduce the shell holder by what ever you need to set the shoulder back to the proper dimension.
You can take the shell holder and a sheet of 400 sand paper and sand off the shell holder be rubbing it on a smooth steel plate or any straight surface.

All brass should enter the chamber without much resistance. That means proper case length and even neck walls. These wee cartridges are high pressure round and require special care to make them perform.

I have a 6x47 Handi custom using the same case as the 204 and had a custom bushing die made that full sizes, sets the shoulder back and neck sizes 2/3 of the neck. All the above applies.

MOGLEY · « **Reply #17 on:** April 13, 2007, 05:38:49 PM »

I am using a pacific c press. Single stage. When the shell holder is up, it is up with zero left over . The shellholders are rcbs as well. I will mic the base to see whats up but would milling the end of the die down ( on a lathe) do the trick?

quickdtoo · « **Reply #18 on:** April 13, 2007, 05:45:08 PM »

I've had to do exactly what Fred suggested recently, just flat sand the top of the shell holder so the ram will push the case farther into the die and set the shoulder back just a tad, doesn't take much. I used 220 grit emery cloth on a piece of plexiglas to do mine, keep rotating the shell holder as you sand to try and keep it even, it works fine.

Tim

just bill · « **Reply #19 on:** April 14, 2007, 01:31:23 AM »

Along with the fine advise already given by those with more knowledge than I, here is a simple way I have found helpful in keeping my Handi rifle p.o.i. where it should be.

a) Cleaning- I only deep clean the bore with a solvent bath periodically as a minimum needed. Between at the range, hunting, etc. I run a dry (no chemical) bore snake through one time, every 7-10 shots. From the cold, fouled to the point of one dry bore snake pass bore, my point of impact is consistent for up to 10 shots before needing the dry pass again. This may not be doable if you have a noted heavy copper fouling caliber

b) OAL of cartridge- I just worked up a load this week. I noticed with the exact same powder charge and primer, bullet in my once fired neck sized cartridge, as I increased my OAL from spec to near maximum in my rifle and back. My POI groups went from vertical to horizontal. I settled for .016” off the lands. You may want to try seating your bullet .010” - .015” from the lands and see what happens?

If someone feels either of these examples would be of no benefit to the problem please do point it out along with "why". It seemed to work for me but I am not sure why from an engineering pov and always like to learn. Maybe more consistant pressure with the OAL closer to the lands in the long throated Handi?

If you try either and they help, lets us know.

MOGLEY · « **Reply #20 on:** April 14, 2007, 03:05:35 AM »

I just took out the decapping pin and ran the shells thru with the new adjusted shellholder. Now they all feed into the guns easily and all the way. I found the hornady brass better for "after" sizing than the winchester as the winchester shoulder pushed in. I only did 3 of the winchesters and decided to just shoot them thru and let the next resizing take care of them. I suspect the necks are a bit thicker. I am going to mic them after shooting. I will be shooting the new loads shortly and hopefully watch the groups be what they should be. I cleaned everything real well last night too. more to come.

MOGLEY · « **Reply #21 on:** April 14, 2007, 11:51:24 AM »

Well thats the last time I use those stupid smileys grrrrrrrrrrrrrrrrrrrrrrr I just lost the entire post I spent the last ten minutes writing

MOGLEY · « **Reply #22 on:** April 14, 2007, 12:02:31 PM »

heres today's results in a nutshell I am not writing everyhing out twice.

Found the case lengths to be 1.87 versus proper length of 1.84.
so I used new brass for the days experiments
New brass did away with the vertical strings. So did resizing already loaded rounds. They fit like they were supposed to.
Varget was not working. 29.5 grains was overdriving the lands sending bullets down range tumbling. Verified by one pointing back at me stuck in the advantec plywood.
lesser grains of varget got better but 25.5 grains of 322 worked very well keeping a 5 shot group in the 1 1/2" bullseye.
oal length on the trouble rounds had somehow gotten to be 2.29 instead of 2.250 for the hornady 32 gr v-max specs.
A very productive informative day. Neighbors are getting used to me shooting I think.
sure is nice to hit what you are aiming at!!

THANKS FOR ALL THE ADVISE! I have learned a lot since buying this gun.
Anything else I am missing??

quickdtoo · « **Reply #23 on:** April 14, 2007, 12:51:25 PM »

Glad it's working out for ya. If you haven't already been there, check out www.204ruger.com lots of info there, both data and on their forum.

I just checked my 204 loads with the 40gr Vmax, I can reach the lands at 2.290", my COL is just shy of that, same as Mitchell uses only we're shooting BL-C2, a max load for him, I'm still working on it.

If you want to use smileys, disable spell check, that's what is causing the problem, Matt is gonna work on fixing it, but he has more important matters to deal with at the time.

Tim