has anyone had problems groupin boattail 6.8 rounds

[stag76.8]

Get ya some AA-2200, and try that with the 110 Hornady BTHP. 28.5 gr. in my RRA goes sub MOA at 100 yds when my eyes cooperate. I'm using Remington LP (CCI-34) brass, and the RRA is a 16" 1:10 spec II barrel. Avg. fps is about 2680 +-.

This is a very accurate load for me too. After reading this thread and making it to the range yesterday, I loaded 110 gr Nosler AB's with used Hornday brass, CCI 400 primers, 28.5 gr of AA2200, and loaded to 2.270". A 3 shot group at 100 yards measured 0.643" and averaged 2,775 fps. Hornady 110 gr HPBT's with Hornady brass measured 0.412" and averaged 2,732. Since you're using SSA brass I've found that 1/2 grain more usually gives the same velocity and even though you should work your way up and check for pressure along the way. The SSA brass is usually a little less consistent and the groups opened up and were slower, but still under MOA.

[SpitFire6.8]

This is a very accurate load for me too. After reading this thread and making it to the range yesterday, I loaded 110 gr Nosler AB's with used Hornday brass, CCI 400 primers, 28.5 gr of AA2200, and loaded to 2.270". A 3 shot group at 100 yards measured 0.643" and averaged 2,775 fps. Hornady 110 gr HPBT's with Hornady brass measured 0.412" and averaged 2,732. Since you're using SSA brass I've found that 1/2 grain more usually gives the same velocity and even though you should work your way up and check for pressure along the way. The SSA brass is usually a little less consistent and the groups opened up and were slower, but still under MOA.

And no sign of over pressuring? Made my Accubonds sub-Moa but at the cost of some ejector swipes, me and this H322, Might have to break down and change!

[stag76.8]

On the Hornady brass there was the occasional swipe, but it was barely noticeable and you had to look hard at to see. The primers looked fine. I've gone higher with other 110's, but the 110 AB's are rather long and take up more room in the case so I didn't go any higher with these and it was a very accurate load.

[rifter]

Another thing that nobody has mentioned yet, is how the muzzle break on your barrel is constructed. The most common is the standard A2 type like the military uses. When the bullet leaves the barrel, the gas blasts past the edge of the bullet and can cause it to wobble around its long axis a bit. It usually isn't enough to cause any major problems accuracy wise, so most people don't sweat it.

When I first got my AR from RRA, that's what was on the end of the barrel. The noise and muzzle blast really bothered me though at the range when I was shooting under the overhead. That got me looking at different brakes. What I settled on was the Troy Claymore. It has six holes in it that divert the gas from the muzzle and run straight out the front of the brake, completely separate from the hole the bullet comes out of. Not only does it direct that supersonic gas -- and the attendant noise -- downrange, but I noticed that my best loads shot a little bit tighter at 100 yds.

That tells me that diverting that gas prevents or eliminates most of the wobble induced in the bullet by a standard type of brake. It also has a saw toothed from rim, so its looks cool and makes it easy to smash a window when you're going house to house cleaning out zombies.

Seriously, though, its something to consider if you're having a case of the wobblies with your boattail loads.

[SpitFire6.8]

Another thing that nobody has mentioned yet, is how the muzzle break on your barrel is constructed. The most common is the standard A2 type like the military uses. When the bullet leaves the barrel, the gas blasts past the edge of the bullet and can cause it to wobble around its long axis a bit. It usually isn't enough to cause any major problems accuracy wise, so most people don't sweat it.

When I first got my AR from RRA, that's what was on the end of the barrel. The noise and muzzle blast really bothered me though at the range when I was shooting under the overhead. That got me looking at different brakes. What I settled on was the Troy Claymore. It has six holes in it that divert the gas from the muzzle and run straight out the front of the brake, completely separate from the hole the bullet comes out of. Not only does it direct that supersonic gas -- and the attendant noise -- downrange, but I noticed that my best loads shot a little bit tighter at 100 yds.

That tells me that diverting that gas prevents or eliminates most of the wobble induced in the bullet by a standard type of brake. It also has a saw toothed from rim, so its looks cool and makes it easy to smash a window when you're going house to house cleaning out zombies.

Seriously, though, its something to consider if you're having a case of the wobblies with your boattail loads.

There is only one problem, I have a Stag 7H , no muzzle break. So would puttin on one help?



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[68WJ]

There is only one problem, I have a Stag 7H , no muzzle break. So would puttin on one help?



WP_000111.jpg

Nope. A target crown is going to be the least intrusive transition between internal and external ballistics.

[rifter]

There is only one problem, I have a Stag 7H , no muzzle break. So would puttin on one help?



WP_000111.jpg

It very well might. The Claymore would be the way to go, or another one just like it. If nothing else, it will cut down on the decibel level at your ears.

[rifter]

Nope. A target crown is going to be the least intrusive transition between internal and external ballistics.

I beg to differ. Even a good target crown is going to allow the escaping gas to contact the bullet base. What I described diverts the gas away from the base, so it cuts down on potential disruption. If you have some hard data to show a target crown is better, I'd like to see it.

[68WJ]

I beg to differ. Even a good target crown is going to allow the escaping gas to contact the bullet base. What I described diverts the gas away from the base, so it cuts down on potential disruption. If you have some hard data to show a target crown is better, I'd like to see it.

So you contend that taking his Stag7's barrel, getting it threaded and adding a claymore will increase the accuracy over his factory target crown? I would also like to see this hard data. Yes, escaping gasses contact the base, but as long as they are symmetrical the effect is minimal. Unless the claymore is constructed that it has bleeds off the gas instead of having an open chamber between the barrel's muzzle and the device's secondary muzzle, there should be no beneficial affect to the bullet. There is even potential for increased turbulence if the gas is allowed to pass the bullet in that gap before exiting the device. I am not familiar enough with its innards to speculate.

A good crown is the last impression for accuracy that the barrel can make as the bullet begins its flight, and every muzzle device attempts to not screw that up while also improving on some other need (flash signature, muzzle climb, etc). I will see what hard data I can come up with.

[rifter]

So you contend that taking his Stag7's barrel, getting it threaded and adding a claymore will increase the accuracy over his factory target crown? I would also like to see this hard data. Yes, escaping gasses contact the base, but as long as they are symmetrical the effect is minimal. Unless the claymore is constructed that it has bleeds off the gas instead of having an open chamber between the barrel's muzzle and the device's secondary muzzle, there should be no beneficial affect to the bullet. There is even potential for increased turbulence if the gas is allowed to pass the bullet in that gap before exiting the device. I am not familiar enough with its innards to speculate.

A good crown is the last impression for accuracy that the barrel can make as the bullet begins its flight, and every muzzle device attempts to not screw that up while also improving on some other need (flash signature, muzzle climb, etc). I will see what hard data I can come up with.

I didn't say it would be better, I said it might be. A target crown is obviously going to be better than a run-of-the-mill production line crown, but no matter how good it is you still get the supersonic blast effect past the back of the bullet as it clears the barrel. The Claymore diverts the gases away from the center of the bore at the last instant into six equally spaced channels that run parallel to the bore and out the front of the brake. That relieves the pressure from the gas on the back of the bullet in that last microsecond exiting the bore.

Like I said, I noticed a measurable difference, an improvement, in the accuracy of my RRA when I replaced the A2 with the Claymore. In addition, it redirected the noise and gas straight downrange. That also had the effect of less muzzle jump, which allowed me to make quicker second and third shots because I didn't lose my sight picture. At 200 yards, it was enough to allow me to see the bullet hit the plate through the scope even in rapid fire.

Of course, I started out with a brake, so I improved the situation that was already there. Whether it will have the same effect on a rifle that doesn't have one to start with, I can't say. As I said, at the least it will make it quieter to shoot by redirecting the muzzle blast, and that's worth it by itself.