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Posted: 11/14/2005 4:40:37 AM EDT
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I've got a DPMS conversion kit in a 16' barrel, 1 in 9 twist. Do any of you have a similar setup? If so, what kind of accuracy do you get with the regular 40 grain ammo that's generally available? I went shooting this weekend with it and fired several mags of the Remington Thunderbolts from about 50 feet, and accuracy was all over an 8' target. I switched to some Aguila 60 grain bullets and accuracy increased to under an inch. Is the increased accuracy due entirely to the larger bullet being more compatible with the higher twist rate? Will a different brand of 22LR shoot better than the Thunderbolts? I'm trying to decide whether to keep the conversion or just go with a dedicated upper. The poor man's solution sounded nice, but if I have to keep buying the 60 grain stuff (which is nigh impossible to find except at gun shows, and has a tendency to eject poorly or not at all) then it's not really worth it in my opinion. Thanks in advance. |
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You have 2 seperate problems using the setup that you have. First is the twist rate. 1:16 is the correct twist rate for 22LR barrels. Many have built uppers using 1:12 AR barrels with good results, but anything less than 1:16 is going to be a comprimise. Second is the barrel diameter. 22 LR is .221" where 223 Rem is .224 diameter. The bore of your AR barrel is .003" too large. I would get a dedicated upper if accuracy is a major concern |
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I have a DPMS kit in my 16" Bushy with a 1/9 twist bbl. This weekend, shooting thunderbolt at 50' with my red dot site we were easily able to shoot shotgun shells and 5.56 brass off of target stands. One shot one kill using a bipod. There was a 14 year old girl shooting for the first time in her life as well and she was also able to shoot the brass and shotgun shells easily. |
The 22LR setups are very ammo sensitive relating to accuracy and reliability. My Kuehl can pretty much eat anything now that I have it all tweaked correctly, but some ammo is more accurate than others. Without spending tons of cash, I just get the minimags and they are acceptably accurate. If I want to shoot full auto, I shoot the bulk stuff. You can play with different kinds of ammo as well. I remember reading that with decent ammo shot from a conversion kit, you can keep your groups down to 3 -5 inches at 50 yards. Just realize you arn't going to be able to do that with walmart bulk pack ammo however. |
Take it out to 50 or 100 yards and let us know what the groups are like. Plinking at 50 feet is fine for a conversion kit. Some folks want more accuracy than a conversion kit will provide. I find with the right ammo, you can hit shooting clays at 50 yards most of the time. That is still fun plinking. Thebigruss, if you need more accuracy than that, you need to get a dedicated upper. |
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When I tested .22 LR with M261 in my 1/9 RRA midlength upper, group averages at 25 yards were in the neighborhood of an inch, with some brands running to two inches. The Aguila 60s shot pretty well, with some groups down around a half inch, but they were not worth the expense and the hideous STENCH and the trouble of getting them. Winchester Dynapoints did almost as well at much less cost, no stink, and no trouble to procure. Results in three 1/12 barrels have been much better. One of them will put the Win DPs into 3/8" at 25 yards all day long, another into about 1/2", the third into about 5/8". This is a useful level of accuracy for training and plinking. With the Win DPs, the best barrel averaged about 1 1/4" groups at 50 yards compared to about 3/4" for a dedicated DPMS .22 upper. |
I would think he would get better accuracy with a 16 foot barrel.  |
LOL 
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My experience is limited to a dpms bull barrel upper and a Ceiner conversion in various Bushmaster 1/9 uppers. The Dpms dedicated upper was a serious tackdriver with match ammo and pretty darn good with any standard velocity ammo. It also shot some high velocity stuff pretty good. There were some exceptions with some brands or types shooting much worse or much better than expected. The Ceiner still has me amazed ,looking at everything envolved (barrel size,twist rate,and distance the bullet must jump to hit the start of the rifleing ) it confounds me how the bullets hit anything at all. Some brands or types of ammo do shoot horrible but after getting my unit broken in and smoothed up I find is will shoot great with selected standard velocity ammo . Almost any of the entry level standard velocity match ammo (CCI Sandard, Wolf,Pmc scoremaster) will shoot 1 1/4" ten shot groups at 50 yards .This is with a factory Bushmaster 1/9 twist , RRNM trigger , good high power scope , and a steady bench and sandbags . I feel the trigger is the thing holding me from better groups .Most of the "match" AR triggers won't run a .22lr upper or conversion . Try this--Shoot a brick or so of high velocity stuff to wear it in and slick it up, clean well and lube. I like plain silicone spray. It slicks everything up but is dry so not so much of the rimfire crud will stick . Then try a couple brands of standard velocity match ammo. I suggest Wolf,Pmc Scoremaster,or eley practice . If the standard velocity won't run your gun try Pmc Zapper . Good luck! hope your unit will shoot as well as mine does . |
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1/9 is the optimum twist for aguila SSS 60grain. 1-16 for std .22lr. That means yeah your groups are always going to suck with std ammo. The DPMS dedicated unit is impressive. under an inch at 50yds with std, of course it would probably shoot aguila like crap. |
Hmmmm... maybe that's why I'm shooting like crap: too much of a good thing. Guess that's what I get for ordering a heavy barrel. |
Almost anything will shoot better than the Thunderduds. My experience with a 20" 1/9 and a Ciener kit is that the 60gr SSS didn't shoot any better than any of the bulk ammo like the Fed. 550 packs from Wal-Mart. I'm sure you'll be able to find something in the buck-a-box price range that works for you. I've had good luck with the Fed 550 packs and also with the Rem 550 packs. CCI Blazers too. Only so-so luck with the Xperts. Sometimes they run well, sometimes I get a lot of jams. |
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