75 gr Hornady HPBT Match bullets exploding

[hpshooter65]

I'm shooting Hornady 75s on top of 24.0 grs of Reloader 15 in new Winchester brass and CCI primers, and they are exploding about 20 yards down range on an alarmingly regular basis.  I am shooting them out of a match rifle with a 28 in 1/7 barrel.  Bullets chrono at 2775 FPS.  They do not seem to be affected in my service rifle or my buddies match rifle with a 1/8 twist.

Is anyone else experiencing this problem, and do you have any explanation?  The load is extremely accurate - when it gets to the target.

[Bigeasy]

I never used that particular bullet, but it sounds like it is disintegrating prior to reaching the target, which should be unusual for that bullet, as it is designed to work in a fast twist barrel at the approx. velocities you are achieving.
 
I wonder if that particular lot of bullets have abnormally thin / soft jackets; if your bore has a slight burr or defect in the rifling that is stressing the bullet jacket, or some combination of the two?
 
I would try the same bullet from another lot #, and if the problem continues, switch to another bullet, assuming that it is only the Hornady 75 that is giving you problems.  Reducing velocity should also work, but that seems like sideways move, at best, treating the symptom, not fixing the problem.
 
Larry

[Larry L]

I think I'd give Hornady a call. Probably a bad batch of bullets but then again, with a 1/7" twist, the rotational energy is way up there. Have you figured just how many RPMs it's cranking? I get just over 285,000 RPMs and that's a lot for a thin jacket.

[Reverend Recoil]

I am not sure what your problem could be.  I have seen 45gr varmit bullets blow up while coming out of a 1-7 twist service rifle barrel. 
My AR15 has a White Oak Armament service rifle upper with a 20" barrel with a 1-7 twist.  75gr Hornady HP match bullets shoot well in my rifle.  How well does your rifle shoot other 75 or 77gr bullets?

[helotaxi]

Sounds like a rifle problem and not related to rate of twist or velocity.  Rough spot in the throat or a hard edge on one of the lands?

[hpshooter65]

Thanks guys, all good ideas.  It's a White Oak upper so it was done right.  It handles 77s and 80s just fine and I have used two lots of bullets.  Guess I'll have to call Hornady - like they're are going to tell me they make bad bullets!

[cwlongshot]

I have read about this and actually had it happen to me with a 22/250 shooting Speer 40g sp with a stiff load of H380 powder. The bullet never reached the target!!!

Rough bore or sharp rifling coupled with thin jackets and ESP fast twists could easily account for this.

CW

[tacklebury]

I had 2 boxes of .45 caliber 250 gr. regular XTP's do this also.  They were blowing up at about 50-70 yards though.  I wasn't at their normal terminal velocity of 1600 fps either.  Was a minimum load of H-110 in my .45 Colt Blackhawk.  I switched to the XTP magnums and problem solved.  Not all barrel twists, even those rated as the same, are identical.  You could have a slightly tighter twist than your buddy's or you might have a burr in your barrel or something destabilizing the bullet.  Have you bore scoped it?  If not, might want to look for recessed or constricted areas, especially around sights, lugs or similar features if the barrel has them.