Confused... (Update!)

[Magnum Mike]

Since I seemed to have good luck last time with the am240 and the half grain heavier load, I put together a several more and ran out to give them a try. Almost half showed signs of instability. So I bumped the load another half grain and gave it a try. No difference. Another half grain and this time I drug the chrono with me as it seemed like the previous load was now going super. Sure enough, the loads running over 1150fps and I still have stability issues.

Very disappointed that this 9.5" Core15 1-8" just won't stabilize the heavies. If I could get a hold of some 240mk's I'd give them a try but I doubt they'll stabilize either. I'm sure it will do fine with the 220mk but they don't tumble on impact like the heavier bullets will.

Now that I've f1'd it to be an sbr, I'll likely have to buy longer 1-7" barrel (don't see any other 9.5" barrels) and have it cut and threaded. Whoever came up with this 1-8" crap should be smacked in the back of the head! I should have paid more attention when I bought it but it was during the panic and was the only barrel I could find...live and learn.

[danner]

If I could get a hold of some 240mk's I'd give them a try

Midway has them on sale the last time I checked.

[darr3239]

Now that I've f1'd it to be an sbr, I'll likely have to buy longer 1-7" barrel (don't see any other 9.5" barrels) and have it cut and threaded.

Don't do that. It's the lower that's SBR'd and you can put any other barrel on it. Keep the original barrel if you want.

[Magnum Mike]

While this core15 barrel seems to do fine with supers, I've yet to find a sub load thats stable. My primary interest in the BLK is suppressed subs. It seems I going to have to go 1-7" to get what I want.

Anyone seen a 9.5" barrel in a1-7?

[r.tenorio671]

While this core15 barrel seems to do fine with supers, I've yet to find a sub load thats stable. My primary interest in the BLK is suppressed subs. It seems I going to have to go 1-7" to get what I want.

Anyone seen a 9.5" barrel in a1-7?

Ballistic Advantage currently has a Fathers Day sale going on, $120 for a 9.5" barrel in 1:7", plus many other choices at lower & higher prices.

http://ballisticadvantage.com/shop/barr ... ckout.html

[TRshootem]

My 16" 1/8 twist, carbine gas AR is very accurate with supers. I never could get that Lee bullet to stabilize, even in my RARR.

I think if it was hollow pointed like I've seen someone do, it might be the ticket. I had high hopes for the Lee in the little Ruger, but so far not happy. I am going to cast a new batch, being very careful to get a good pour and try them unsized again. No way I would shoot them through my can.

[Magnum Mike]

While this core15 barrel seems to do fine with supers, I've yet to find a sub load thats stable. My primary interest in the BLK is suppressed subs. It seems I going to have to go 1-7" to get what I want.

Anyone seen a 9.5" barrel in a1-7?

Ballistic Advantage currently has a Fathers Day sale going on, $120 for a 9.5" barrel in 1:7", plus many other choices at lower & higher prices.

http://ballisticadvantage.com/shop/barr ... ckout.html

Anyone have experience with this companies barrels? I'm very tempted...

[danner]

Anyone have experience with this companies barrels? I'm very tempted...

Yes.

r.tenorio671 has one and I do too.

[r.tenorio671]

Anyone have experience with this companies barrels? I'm very tempted...

Yes.

r.tenorio671 has one and I do too.

...actually, I have used them in 7 builds, 4 in 5.56 (7.5, 8, 16) and 3 in 300BLK (9, 10.1 & 16) Performance was way better than I expected, considering the costs. Upon initial receipt of my first one, I was extremely surprised and pleased by the overall craftsmanship and finish. Since then I use them exclusively.

[Dolomite_Supafly]

Those bullets are not unstable, they are kissing the end cap and becoming unstable which is a totally different problem.

I designed the bullet you are using and it remains stable in most 10 twist barrels at 1,000 fps or faster so I find it really, really hard to believe it is unstable in an 8 twist barrel. What is more likely is the silencer is tilted and the bullet is contacting the end cap upon exit.

You do not mention it but are these powder coated? I would, if you are dead set on shooting cast, because shooting bare lead through a silencer will fill up your can with lead. This will reduce performance as well as increase the weight of the silencer. But powder coated or not this is not a stability issue but an issue caused by the bullet kissing the end cap as it exits.

I see you are using a QD mount, is it seated directly against the shoulder of the barrel? You cannot use a crush washer with a silencer as they will tilt the silencer off center in relation to the bore. If you must clock a QD muzzle device you MUST use crush washers.

Because you are only getting marks at the 12 o'clock position my gut feeling is either the silencer, the barrel or the brake is not concentric to the bore. The only way to tell which one is to move the muzzle brake and silencer to another gun to test. If the problem goes away then it is the Core 15 barrel. If it doesn't go away then it is either the muzzle device or the silencer and they need to be returned to the manufacturer for inspection.

The instability issue at the target is not because of the bullet being unstable but because the bullet is hitting the end cap. That is like having a bad crown. If the bullet is unstable then you would have those marks all around the exit hole of the silencer. Because it is only at one spot, 12 o'clock, the bullets are stable but they are becoming unstable from kissing the end cap upon exit.