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Old January 23, 2013, 08:14 PM   #1
tank1949
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AR BULL BARREL Accuracy

I have an AR old slick side upper that I installed a RR 24" .223 wylde bull barrel on. It is ss with 1x8 twist. It is heavy!!!! The carrying handle has been machined of and a weaver flat top style mount bolted. If you look at it from a few feet away, it resembles a flat top. It has an accue wedge and I also lay a piece of tape between upper and lower to force a tight fit. The gun will not consistently shoot accurately. I am a stickler for accuracy and I wanted to build a super varmint rifle. SUB MOA is demanded. I have a 15 x Leupold older LPS mounted on it. I have tried combinations of H4895 and IMR 8208 and wasted 500 + 69 gr SMK bullets. Working up loads, I have digital scale and Redding match powder thrower. I get no bullet run out, which is startling to me. But I have gauged them. My 30-06 is another story. I have to adjust bullet run out almost every time. Nonetheless, I get excellent groups during one range event and then come back with a whole bunch of the best loads from the first trip only to sling them all over paper and have the group shift a couple of inches. Group shifting is horrible. Mind you, I always shoot this rife at 200 yds and make sure no wind. Loads go from 1" groups to 2 1/2 " groups and may be 2 inches low or high from previous trip. A fellow at the range suggested that it might be that the barrel is just too heavy for the receiver and any excess pressure from me on rifle/stock/grip from magazine back might be causing inconsistencies. I even go so far as to sort and weigh Winchester brass for this rifle . Any recommendation of any who have built this type rifle and experienced the same problems????
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Old January 24, 2013, 02:58 PM   #2
Jimro
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1. Sounds like a bad scope or scope mount, have you tried a different scope?
2. Do you have the barrel free floated?
3. What primers are you using? How are you seating them?
4. What press are you using to reload?
5. How are you trimming?

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Old January 24, 2013, 03:21 PM   #3
hodaka
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Your scope mount seems a bit questionable to me, at least how it is described. Also, your barrel may not like 69 grain bullets. I bought a heavy 8 twist barrel from a friend because it would not shoot 69's. He had given up. I loaded up some 52's and it shot them into one hole. I have since learned how to make 77's shoot well. Most fast twist rifles shoot the 69's but not all.
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Old January 24, 2013, 09:43 PM   #4
tank1949
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Thanks to all.

Trim with Dillon, CCI sr, Win brass 91.3 +-.7 weighted hulls, flush primers seated, 69 out as far as magazine will allow, runout +-.0005 (incredible).

I haven't tried another scope. I was concerned more about weight of barre/upper being too flexible.

I have a lot of H4895 and IMR 8208 and a lot of 69 smk and hornady 52 gr match. I could try the lighter bullet?
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Old January 24, 2013, 09:45 PM   #5
tank1949
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The press is RCBS single stage and barrel totally floats in tube.
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Old January 24, 2013, 10:07 PM   #6
mc223
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There is the possibility that you have a bad barrel. Also inspect the muzzle for damage and Use a Q-tip in the muzzle to check for burrs.
Sometimes trying to run your bullets too fast can effect accuracy in a bad way.

I too have had better luck with 77grainers in the 1 in 8. VV N540 Re 15.

I have an old Bushy 1 in 9 that shoots the 69s very well with Varget and H 4895.

good shootin
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Old January 24, 2013, 10:15 PM   #7
BoomieMCT
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I have a 16" bull barrel from RR. It is very consistent with its (excellent) accuracy. It likes heavier boolits - 75grain is what I normally use.

Only thing is the free float tube was not torqued properly from the factory. When I replaced the handguards I torqued it properly and saw a big boost in performance (went from good to great).
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Old January 25, 2013, 11:53 AM   #8
madcratebuilder
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Have you tried using quality commercial ammo to rule out everything but the reloads?

I have the cheap DPMS mini SASS 1-8 bull barrel. I've gotten .8 moa (NM irons) from a $200 barrel, and it shoots anything I feed it.



Yes, it's heavy, but shoots like a laser.
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Old January 25, 2013, 01:51 PM   #9
tank1949
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tried hornady match I think it was 77 or 75 grain. worse! Attaching NF and trying this next week to rule out scope. thx
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Old January 25, 2013, 05:11 PM   #10
Jimro
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If it doesn't shoot 69, 75, or 77gr match bullets tight with the 1:8 twist, I would try the 52gr match bullet.

If it doesn't shoot that bullet tight then you really need to check your optics.

I don't know how much material was removed off the top of your A2 style upper to mount that rail. But I would expect aluminum to break before bending much, so as long as it hasn't broken, it leads me to suspect that your scope or mount is at fault, if your rifle won't print 52gr pills reliably.

If you are worried about the upper receiver, get a flat top slabside, that is as rigid as you are going to get in aluminum.

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Old January 26, 2013, 11:07 PM   #11
Nanuk
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I like the slick side DPMS for a heavy barrel.

http://www.midwayusa.com/product/138...flat-top-matte
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Old January 28, 2013, 07:38 PM   #12
tank1949
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That's cheap and of course out of stock. All these gun show Gypsi have raped supplies hoping to make a buck off the Marxists DC threats. I have a flat top but have ordered 16 RR barrel for it.
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