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Posted: 1/28/2010 10:55:21 AM EDT
| Hi all im working on a new build for shooting steel 2 gun course.I will be using a yhm spectre upper in 16 inch.carbine targets will be 75 yards up to 800 yards. i will be using 55 grain fmj only the gun will be used for nothing else.i need to know what twist rate will work best for this.i know subject has been beat to death but i have already bought an upper with a improper twist for what i wanted and dont want a repeat lol.I bought a bushmaster 24 inch barrel in 1-9 to shoot black hills blue box softpoint and it grouped at 4inches at 100 yards .So i hadt to go to 36 grain v grenades to get a sub moa group at 100.or shoot 60 grain plus match bullets which are worthless on squirrels hehe.So that being said please hook me up with the proper twist for my 2 gun setup please––- TIA |
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You are asking what is the best twist rate for 55gr bullets in a 16" carbine that you want to use out to 800 yards? Have you ever shot at 800 yards? I think you need to rethink what you want because 800 yards is FAR too optimistic for a 55gr bullet.
You would need a 1/10" to stabilize a 60gr bullet reliably. The 1/9" YHM upper will be fine, if that is what you want. You are not going to find that many 1/12" twist barrel on the market, at least for an AR-15. Lastly, grammar and punctuation helps in trying to figure out what you are attempting to say. |
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Optimum for 55gr FMJ is probably 1:12.
800 yards is extremely optimistic for 55gr lead core bullets. As with any barrel, the particular load that works best will be what your particular barrel likes... there is no way to predict exactly what will be best in any particular barrel. Getting closer to optimum twist rate should give you a better chance of good performance with your load of choice. Obviously getting a good match grade tube is helpful for accuracy regardless of the twist rate. If I was you and needing a 5.56 to perform at 800m I'd be looking for a very high quality barrel in 1:8 and shooting 70-something grain match hollowpoints. And longer than a 16" barrel as you need all the velocity you can get at that range. |
| Yeah im not an english major.As for shooting 800 yards yes ive shot at basketball sized chalkrocks with an old m-4 with the sights maxed and hit probably 80 0/0.Will the round make more then a tiny wiff of dust off rock at 800=no.I am shooting a personal course with my sons and friends, its for fun not competition.I have a 24 inch grendell for the serious stuff.that being said and from what everyone has posted im thinking a 1-8 to be the best compromise? |
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I shoot 55gr & 60gr soft points, 60gr moly v-max and 55gr FMJ Black Hills (blue box) all average 1-1/2 to 2" out of my 2 SPR's..
I shoot the Black Hills (red box) 55gr Barnes TSX and Federal 62gr Fusion in these rifles and get ocassional 1 to 1-1/2" groups.. There is either something wrong with your gun or your shooting as this ammo weights work fine with 3 different rifles i have that are 1-9.. The only problems i have is shooting the heavy stuff (68, 69, 70 and 75gr) at long range. The lighter of the heavies group 3-5 MOA and the 70 and 75 have tumbled on me at 300-400 yards. therefore i dont shoot them. |
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Ooops Features Include:
* Mil. Spec. Forged 7075-T6 Aluminum YHM Flat Top Upper Receiver * "T" Marked Upper Receiver * Forward Assist * Mil. Spec. Bolt Carrier Assembly * 16" Chrome-Moly Vanadium Steel Barrel, Heat Treated to RC 25-32 * Chambered in 5.56 N.A.T.O., Chrome-Lined with either a 1:9" or 1:7" Twist * YHM Diamond Fluting Improves Rigidity and Aids in Barrel Cooling * YHM Phantom 5C2 Flash Hider / Compensator (YHM-28-5C2) * YHM Specter Length Diamond Handguard (YHM-9637-DX) * YHM Forearm Endcap (YHM-9484-B) * YHM Low Profile Gas Block (YHM-9383) * YHM Forearm Mounted Flip Front Sight (YHM-9627) * YHM Flip Rear Sight (YHM-9680) Total Weight: 4.8 Pounds They only make a 1-7 or 1-9 lol |
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Quoted:
Hi all im working on a new build for shooting steel 2 gun course.I will be using a yhm spectre upper in 16 inch.carbine targets will be 75 yards up to 800 yards. i will be using 55 grain fmj only the gun will be used for nothing else.i need to know what twist rate will work best for this.i know subject has been beat to death but i have already bought an upper with a improper twist for what i wanted and dont want a repeat lol.I bought a bushmaster 24 inch barrel in 1-9 to shoot black hills blue box softpoint and it grouped at 4inches at 100 yardsmoa group at 10 .So i hadt to go to 36 grain v grenades to get a sub 0.or shoot 60 grain plus match bullets which are worthless on squirrels hehe.So that being said please hook me up with the proper twist for my 2 gun setup please––- TIA This quote makes no sense. The 1-9 will work with the light weights but it will work well (at least most) with the 60gr. Generally 55, 60 and 62 work fine for M.O.M. |
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