Hello fellas, I found a couple full boxes of 55 gr Nosler BT's I forgot I had and a few loaded rounds left in a bag under some old gun cases my dad gave me some time ago. The loaded ammo is loaded with 25 gr of Varget and was used in an old 223 bolt gun. Since then I got a S&W mp15 with a 20" barrel and 1-8 twist. These old rounds shoot good out of my AR but the velocity is not as high as the other loads I'm useing in my AR. In fact, out past 150 yrds, it drops off to 3" low at 200 yrds. I use TAC & Exterminator with a Sierra 55 Gameking in the AR and they shoot much flatter if you can call the 223 a flat shooting round. The Sierra manuel gives 3100 fps out of an 20" AR barrel. Anyway, I was wondering if anybody uses the BT's in an AR and what powder do you use to boost velocities ? The BT is a fairly longer fragle bullet and maybe should'nt go too fast, I don't know. The Nosler reload guide I have does'nt push them much past 3000 fps in a 24" barrel. I'm sure the AR is'nt nearly that fast even. I would just forget about them, but I would like to use them up. I'm shooting mostly coyotes. Any advise ??

what is the 100 yard p.o.i.?

Did you zero for 100 yrds?

What is "much flatter" 1 inch?

Load 'm up, shoot 'm out!!!

Yup, load em and shoot em!

Them coyote wouldn't know or care what brand bullet hits them.
Any brand bullets kills them coyotes or other varmints as dead as the others.

Load-em and shoot-em !!!

The varmint BT's have been laboratory tested to over 5,000fps..........They're only fragile when they hit something !!!

Well guys, I guess you're right. Maybe I'm makeing a mountain out of a mole hill. I just tought I'd like to kick them up a little faster that's all. I'm not sure what the 100 p.o.i is, some where around 2400 fps maybe( 700 ft/lb), but I'm about 1 1/4" high at 100 and I zero at 150 yrd. I think it's alittle excessive to drop 3" in 50 yrds is all. I might just try some H335 and speed them up some, then shoot'em up next summer. The Varget does'nt quite fill the case but gives good accuracy at 25 grs. Any other thoughts before I head to the bench ?

Oh yea, my other load that does best for the AR is 25 gr of Exterminator around 3100fps, zero to 1/2" low at 50 yrd, 1 to 3/4" high - 100, zero at 150, 1 1/2" low at 200.

i know your talking about an AR with 55gr BT's. but i have always used the noslers in my bolt gun. and gotten a fairly high velocity range with them. i havent dond velocity testing with the 55 grainers (supprisingly), but i have gotten the 40gr nos BT up to 3413fps with 28.7gr of hodgdon bl-c2. and the 75gr hornady A-Max up to 3026fps with 27gr of bl-c2. with both of these they bullets are seated pretty far out. im thinking too much for the magazine of an AR especially for the 75's

mp15 with 1:8 twist? Are you sure it's not 1:9? Look it up before you load it.

According to my data, a 1:8 twist will best stabaleize an 80gr BT projectile, given, you can go lower, but you won't get the distance you want for coyote charming.

I was under the impression the S&W MP15's were all 1:9 twist rate which would best stableize a 73gr BT projectile.

My two cents says recheck your data before you load. I'm sure you know what you are doing, but I make stupid mistakes all the time. Just last month I wasted 200 Sierra Match King 9mm loads by using too much powder. Let me know how it turns out. I like to hunt with AR's as well.

Regards,

Andy Widener

Andrew - You are being too hard on yourself with restricting twists to a bullet weight. I have had 1:9's that would stablize a 75 Amax just fine. I shoot 52 grain match bullets in a 1:7 into little bitty groups. The Greenhill formula is a gudeline. Actually, it is bullet length and bearing surface that impacts bullet stabilization more than the weight. It is just that 80 grain .224 bullets are longer than 45 grain .224 bullets.

Csid - It does not sound like you have chronographed this load. From my experience with AR-s and varget - 25.0 gr is not too hot. I run closer to 27 grains for my 55's. I would guess you are about 2800 fps. if you are siginificantly different form that - you may want to pull some bullets and check that charge weight. Also What is your sight height above the bore?

If you use 3" the BT at 2750 gives +1/2" at 100 for a 150 zero and is down 2.5" at 200....

compare that to a game king at 3100 fps... +.25 at 100 down 1.5" at 200.


FWIW - I would not zero at 150 with the AR for that reason. I actually set my guns up so the max elevation is at 150.

I use a 55 V-max at 3100 fps and set my Zero at 214... I am +1.5 at 150 and only -2.0 at 250. 99% of the coyotes I kill are under 300 yards. With this setup I hold middle of fur for any shot from 25 to 275.

AR2206 55grn projectile 24.5 grains powder is my pet load in the bolt gun. 3/4" high at 100yrds does the biz for me.