Author Topic: AR15 shotgroup (Read 1086 times)

DANNY-L · « **on:** June 16, 2011, 06:14:22 AM »

Can anyone explain this group,it has been the same with all loads I've made from 55gr.-69gr. The rifle is scoped with a leupold varix-ll 3x9 which is locked down tight. Factory 55gr.fmj hit the same also. Shots are from a bench with a lead sled. Barrel is cleaned with a bore snake between groups,and is cleaned with a brush about every 50. I'm going to be gone for about a week,hopefully when I get back there will be an answer.Thanks

SHOOTALL · « **Reply #1 on:** June 16, 2011, 06:34:06 AM »

If it were me I would try off sand bags one under hand guard and a rice bag under the toe. There is alot going on inside an AR during recoil with bolt , springs and damper . Maybe the lead slead confines movement in a way that is not consistant. Also is the mag touching/hitting while fireing ?

DANNY-L · « **Reply #2 on:** June 16, 2011, 06:53:55 AM »

Nothing is touching but the forearm and buttstock,I was kinda wondering if sandbags might be a little better considering the rifle,but the leadsled is very sturdy (maybe to sturdy?)

SHOOTALL · « **Reply #3 on:** June 16, 2011, 07:32:27 AM »

That was my thought also , it wasn't recoiling the same shot to shot . Are the upper and lower tight or is there play ?

DANNY-L · « **Reply #4 on:** June 16, 2011, 08:17:25 AM »

Everything is tight,round count on this is probably less than 6-700. I also had the trigger worked on by bill springfield and the ave.pull is 4.2 lbs.

SHOOTALL · « **Reply #5 on:** June 16, 2011, 08:20:04 AM »

I would try the sand bags .

DANNY-L · « **Reply #6 on:** June 16, 2011, 09:06:40 AM »

Shooting from sandbags,everything else is the same. I was kinda rushed for time but just couldn't resist.Thanks

SHOOTALL · « **Reply #7 on:** June 16, 2011, 10:22:49 AM »

better, To be honest I have had zero shift and group problems with my lead slead.

DANNY-L · « **Reply #8 on:** June 16, 2011, 10:42:37 AM »

With my bolt guns I swear by th lead sled but like ya said there's alot going on when fireing an ar.

SHOOTALL · « **Reply #9 on:** June 17, 2011, 03:32:30 AM »

I find point of aim changes when I go from slead to shoulder with some bolt guns and my encore BP gun.

huntducks · « **Reply #10 on:** June 17, 2011, 05:58:01 AM »

Quit cleaning the barrel so much many guns like a dirty barrel.

DANNY-L · « **Reply #11 on:** June 20, 2011, 02:20:30 AM »

Quote from: huntducks on June 17, 2011, 05:58:01 AM

Quit cleaning the barrel so much many guns like a dirty barrel.

Very well could be right,I've seen it happen a few time. I read not long ago that you should only clean the bore when the shotgroups start falling apart,but dang that's hard to let a rifle stay dirty but if it works that's what ya gotta do.

KansasPaul · « **Reply #12 on:** June 20, 2011, 05:20:03 AM »

There are a lot of variables with AR rifles from barrel twist/configuration to chamber size. Is the barrel chrome lined or stainless...etc.

First, you have to understand that most ARs shoot groups that spread 2-3 inches, which is good for a combat carbine. Even the upper end AR manufacturers state accuracy in 2" @ 100yds. Assuming that the target in the photo was shot at 100 yds, your grouping doesn't look bad to me. I'm also assuming that you are shooting a carbine length rifle. You also didn't mention if the rifle is chambered for 5.56 or .223 - they may look the same but chamber specs are different and you can't expect match accuracy. The most accurate ARs will have a free-floated barrel, chambered in .223, and a good trigger. The other consideration is the time between shots - thin, short barrels heat up fast and the shot group will spread.

My best success with reloading for ARs has been using Varget and 55grn Sierra boat tails - you might have to play around a little more with combos to find the one that works best for you. Try to let the barrel get a little dirty - not sure if it will help, but it might. The other thing you might do is weigh your bullets to see if there is a significant difference in weight - you might be surprised by the inconsistencies of some bullets. Weigh your brass as well so minimize inconsistencies and be sure to use the same head-stamped brass (.223 has small case capacity and little things that effect capacity make a difference) - always full-length size your brass.

Be patient with the rifle - keep working on it. I spent the better part of a year working out the "bugs" in an AR that had "the best combinations" but wouldn't shoot well enough for me. I obtained a copy of "Precision Shooting - Reloading Guide" and read the section on High Power (Gas Guns) which helped me manage my expectations and understand the limitations to accuracy inherent in AR type rifles.

Paul

DANNY-L · « **Reply #13 on:** August 01, 2011, 09:41:26 AM »

I bought the rifle slightly used,the guy told me it has a LME upper chambered in 5.56,16"carbine Spikes tactical lower,I had the trigger work done by Bill Springfield to 4lbs,55gr.bullets I've tied are hornady sp and speer sp both flat base. Powders I've tried are imr 4064,varget,h335,a2230 with several different weights of each,oal I tried are by the manual or to mag.length.

KansasPaul · « **Reply #14 on:** August 01, 2011, 03:07:14 PM »

Hi Danny. I'm not familiar with "LME" (LMT yes, but LME no) - anyway, I am assuming you are working with 1/9 twist which should stabilize a 55 grain very well. One thing I noticed is that your rifle has a standard forearm. If you are shooting for accuracy you need to support the rifle from the lower receiver - try a sandbag under the receiver and remove the magazine - shoot single shot while working up your load. Stick with one powder/primer/bullet and use the "Ladder Method" - you can google it. Basically you will be working up cartridges from the lower to upper pressure ends in small increments and looking for a grouping - further load development comes from there. Don't buy anymore bullets or powder. I would start with Varget and see how it works out.

Most ARs in the carbine configuration with chrome lined barrel and non-free float fore end and standard trigger will only be a 2MOA rifle. Improvements come from a good trigger & free float - but not in all cases. Separate brass cases by head stamp then by weight - this will help. Also be sure to trim all cases. Try using Remington primers as many have good success with them as well. Weigh each powder charge - don't use a measure. You may also want to weigh your bullets for variation as well. This seems like a lot of work, but if you want accuracy this may be the only direction to go. Let me know how it turns out.

Paul

Dezynco · « **Reply #15 on:** August 01, 2011, 05:09:50 PM »

I have found that all of my semi auto rifles tend to shoot poorly from a lead sled. The lead sled works ok for my bolt guns and single shots, but I shoot from sandbags for a final fine tuning. Looking at your picture, I would say that's a darn good group if you do not count the 2 "flyers", the other 4 are just too close together.

A good trigger with little creep and overtravel will tighten up a group tremendously. I installed a Rock River "national match" in my 300 "Whisper" and cut my groups in half. $100 well spent!

I also installed a free-float tube, which helps also, and looks very nice.

Lloyd Smale · « **Reply #16 on:** August 02, 2011, 02:11:38 AM »

dont know paul. Ive got 5 .223 ars and the least accurate one of the bunch will still shoot moa with loads it likes and the best will shoot 1/2 inch at a 100 for 5 shots and thats a 16 inch hbar barrel. could be the lead sled especially if you have a colaspable stock. theres enough play in the stock to cause problems with a rest that wont allow for recoil. I hate to say it but my first guess is you just pulled 2 shots not one. second guess is if it is the real way that gun is grouping and it isnt you that you just need to find a better load. third would be that you could stand to float that barrel. if it consistantly shoots the first 3 into a tiny group then starts wondering its likely could be groups are opening up because your barrel is heating up and because it isnt floated the groups are wondering.

Quote from: KansasPaul on June 20, 2011, 05:20:03 AM

There are a lot of variables with AR rifles from barrel twist/configuration to chamber size. Is the barrel chrome lined or stainless...etc.

First, you have to understand that most ARs shoot groups that spread 2-3 inches, which is good for a combat carbine. Even the upper end AR manufacturers state accuracy in 2" @ 100yds. Assuming that the target in the photo was shot at 100 yds, your grouping doesn't look bad to me. I'm also assuming that you are shooting a carbine length rifle. You also didn't mention if the rifle is chambered for 5.56 or .223 - they may look the same but chamber specs are different and you can't expect match accuracy. The most accurate ARs will have a free-floated barrel, chambered in .223, and a good trigger. The other consideration is the time between shots - thin, short barrels heat up fast and the shot group will spread.

My best success with reloading for ARs has been using Varget and 55grn Sierra boat tails - you might have to play around a little more with combos to find the one that works best for you. Try to let the barrel get a little dirty - not sure if it will help, but it might. The other thing you might do is weigh your bullets to see if there is a significant difference in weight - you might be surprised by the inconsistencies of some bullets. Weigh your brass as well so minimize inconsistencies and be sure to use the same head-stamped brass (.223 has small case capacity and little things that effect capacity make a difference) - always full-length size your brass.

Be patient with the rifle - keep working on it. I spent the better part of a year working out the "bugs" in an AR that had "the best combinations" but wouldn't shoot well enough for me. I obtained a copy of "Precision Shooting - Reloading Guide" and read the section on High Power (Gas Guns) which helped me manage my expectations and understand the limitations to accuracy inherent in AR type rifles.

Paul

DANNY-L · « **Reply #17 on:** August 02, 2011, 08:24:54 AM »

My mistake it is an LMT 1-7 twist,the stock has been pinned (ny) so it is tight with no slop,I do sort brass by hs but don't weigh,I trim brass after each firing. I''ll check into floating the barrel,never seen how to go about it on an ar. I like shooting from sand bags but last year I had surgery on my lower back and had 4 disc fused,so it makes it a bit difficult to bend much,I could build a higher bench and shoot standing that might help. Time to do a little research on suggestions that was just given to me. Thanks

revbc · « **Reply #18 on:** August 02, 2011, 02:33:52 PM »

The 1-7 twist barrel maybe reving your 55 grainers up to much. (If your pushing them fairly hard) The 1-7 was made for fairly heavy bullets, 75-85 gr if my memory is correct.

Bobby

ratdog · « **Reply #19 on:** August 02, 2011, 10:37:30 PM »

try some 62 grn boat tail hollow points mine loves them clover leaves them at 100 yards. even silver bear russian ammo mine don't like 55 grn reloads or therwise.

DANNY-L · « **Reply #20 on:** August 03, 2011, 03:23:49 AM »

I've got some 65gr.sierra and they don't shoot to bad but not exactly great but a bit better than the 55gr,would the 62gr. be much different. To be ny compliant my muzzle break I was told when I bought the gun is permanently attached is it still possible to free float the barrel.

223Pitbull · « **Reply #21 on:** August 12, 2011, 07:07:18 PM »

This is a prime example of how most of my AR’s shot with a clean barrel. The only one that does not seem to be affected is my 458 SoCom.
12 shot group……..notice the first 4

DANNY-L · « **Reply #22 on:** August 13, 2011, 01:29:40 AM »

That is a good example,after 4 shots tightened it up pretty good.

Lloyd Smale · « **Reply #23 on:** August 14, 2011, 03:01:17 AM »

there are two piece foreams that you could use to float your gun without removing the flash suppresor. My 1 in 7 twist colt does pretty well with 55s but does a tad better with 60s. If you are combineing 55s with a slightly lighter load it may be causing you stability problems. Danny a good possibility is you just havent for the right powder bullet combo for that gun. LMTs are top shelf guns and that gun should have no problem shooting at least 1.5 inch at a 100 yards with a load it likes.

DANNY-L · « **Reply #24 on:** August 14, 2011, 05:51:36 AM »

Well I did some shootin useing benchmark,wsr,55gr. speer sp,oal 2.200,sandbags,100yds. My high and low end seemed to be the best. I'll list best 3 of 5 shot & total shot measurements.
3 shots 5 shots
23.1gr. .390" & 1.302"
23.6gr. 1.120" & 1.894"
24.1gr. 1.236" & 1.846"
24.6gr. 1.460" & 2.600"
25.1gr. .678" & 1.102"
25.6gr. .324" & 1.225 this load measured 4 shots touching and 1 outside.
I think I can live with this. I also replaced my hand rails with UTG 2pc qaud that bolt to each other,that and a combination of other changes (powder,rest) all seemed to help. Thanks all for any of the info. you gave.

SHOOTALL · « **Reply #25 on:** August 15, 2011, 03:37:52 AM »

Quote from: Lloyd Smale on August 14, 2011, 03:01:17 AM

there are two piece foreams that you could use to float your gun without removing the flash suppresor. My 1 in 7 twist colt does pretty well with 55s but does a tad better with 60s. If you are combineing 55s with a slightly lighter load it may be causing you stability problems. Danny a good possibility is you just havent for the right powder bullet combo for that gun. LMTs are top shelf guns and that gun should have no problem shooting at least 1.5 inch at a 100 yards with a load it likes.

I don't know where you are now but was the flash welded ? I always hate that never know if there is stress on the bbl after welding but more important the crown is difficult to inspect. If your gun does not come around with load changes it might be worth while to pick up a new bbl if legal where you are now.
Remove the hand guard and try a few shots if you think that is your problem.

DANNY-L · « **Reply #26 on:** August 15, 2011, 05:18:37 AM »

The flash is permanent and the 6 position stock is pinned to be ny compliant. What kind of a moron thought this law up.

SHOOTALL · « **Reply #27 on:** August 15, 2011, 08:40:02 AM »

I have to agree on moron , If the stock has to be solid then I would go with an A-1 stock , that will make things solid in that area . A-1 tock is an inch shorter than the A-2 stock but either will work. I switched to an A-1 on my hunting gun . If you can check look at the crown if all else fails. I have a free floated hand guard , its alum standard length. It has 3 inch rails at 3, 6,9,and 12 on the forward end. It weighs alot . I hunted with the gun last season ( its a 6.8 spc) I wish It had a 16 unch bbl instead of 20 inch and standard gas block with sight . I built the gun and learned there are a bunch of options for this type gun. All have a use maybe but just about all add weight. There are tons of stuff that make the gun more accurate but how much so ? Before you do alot make sure the basics are up to spec. Bolt lock up consistanr, good ammo , solid mount on sights upper and lower tigh fit , crown on bbl good , bbl clean and in good shape ( note while building my gun the first bbl looked like a sewer pipe it had so much trash in it a steel brush would not clean it up. The replacement bbl had wrong size gas port) and other things .