Gunsmithing Chamber question. Please help

[DedicatedShooter]

I recently had my Remington 700 .308 blueprinted and re-barrelled with a Krieger HV SS 26". The barrel was target crowned and threaded to accept a Shrewd varmint brake. I have a question about the chamber that was cut... it is a .308 match chamber and when I checked to see how long my throat is, I found out that I can only load to 2.798" which is .002" under SAAMI specs. (checked with a Hornady OAL gauge)

I haven't been able to find a load that will shoot very well in my rifle since it was worked on. I keep having fliers in my groups. Do you think the throat needs to be extended? Or what do you suggest I check or do? Thanks for the input!

**EDIT**

I should have included some more information in my original thread but I forgot.

All my load testing has been at 100 yds and with a mechanical front rest. I have shot only 5 shot groups.

I have put 40 rounds of FGMM through the rifle as well as 60 rounds of handloads that included many different combinations of powder, coal, and bullets. I have used 175 SMKs and 155 Scenars with Lapua brass and Varget and 8208 XBR powders.

The FGMM shot well except for the fliers. At 100 yds I would have 4 shots at .2",.3", or .4" but all had one flier that made the group more like .7" or .8". So far I haven't found a good handload combo but I also haven't tried shorter COALS. My next test will be: 45.0 grs Varget with a 175smk loaded with .005", .010",.015", and .020" jumps. I will be doing the same thing with 47.0 grs Varget and the Scenars as well as with 45.0 grs XBR and the Scenars. I will also be testing some more FGMM and I WILL NOT be using my muzzle brake in order to eliminate as many variables as possible.

Thanks for the input!

Also,

My muzzle brake is the Shrewd Varmint Brake with ports on the right and left side and none on the top or bottom.

 

[longshooter]

Re: Chamber question. Please help

Your perceived problem has more to do with your particular bullet, bullet weight, and it's nose profile, than with it's resultant C.O.L.

Have you tried seating the bullets to various lesser C.O.L.s, to try to find a more accurate load? Also, you might be in a desirable position for "jamming" bullets, if this is your wish.

As your throat wears, you will be able to seat longer. This might be welcomed.

 

[Jim See]

Re: Chamber question. Please help

If it is the shrewd brake with holes only on the top 180 degrees, then it is the brake causing the problems. Screw it off and try again.

 

[Hateca]

Re: Chamber question. Please help

Also shoot some match ammo to eliminate your reloads.

 

[joemagee]

Re: Chamber question. Please help

I think you will like the short throat in your chamber, my col with a 175smk is 2.79 with .010 jam. about the same as yours, Try loading .010,.015,.020 longer, Might show promise. The nice thing with a short throat is as the throat wears you can seat your bullet longer and still fit your mag.

 

[x ring accuracy]

Re: Chamber question. Please help

Also, What is your definition of a flyer? 1 in 5, 1 in 10 shots? 1" off of the group or 3" off. Just asking to get the snag drilled down.

 

[DedicatedShooter]

Re: Chamber question. Please help

Hey everyone thanks for the input so far, I edited my original post in order to give you all some more info! check it out.

 

[Hateca]

Re: Chamber question. Please help

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DedicatedShooter</div><div class="ubbcode-body">Hey everyone thanks for the input so far, I edited my original post in order to give you all some more info! check it out. </div></div>

Using a front mechanical rest what's under the butt stock? Tight groups and just one flyer I suspect maybe you. Let someone else shoot the rifle and use a rear bag.

 

[x ring accuracy]

Re: Chamber question. Please help

I think its you...and trust me I suffer the same flyers when I get happy over the previous 4 shots. #5 always goes haywire.

 

[DedicatedShooter]

Re: Chamber question. Please help

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: HateCA</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: DedicatedShooter</div><div class="ubbcode-body">Hey everyone thanks for the input so far, I edited my original post in order to give you all some more info! check it out. </div></div>

Using a front mechanical rest what's under the butt stock? Tight groups and just one flyer I suspect maybe you. Let someone else shoot the rifle and use a rear bag. </div></div>

I use a 25lb. Edgewood Gaterbag for a rear bag. My rifle is in a AICS stock and my Jewell trigger is set at 1lb. With the front rest its almost like a bench gun. I have had 3 friends shoot my rifle with the FGMM ammo and we all have had fliers and it's not always on the 5th. shot of a really good group. We all compete in 600 and 1000yd F-class matches with our .308's and .50bmg's so we are experienced shooters. But I do know that we pull shots and have bad days at the range just as much as any other rifle shooter but it does seem like we all have consistent fliers with my rifle.

I am going to be doing some more load developing once the snow and sub-zero temps here in NE Ohio go away and I will be shooting without my muzzle brake, maybe that's causing a problem?

 

[longshooter]

Re: Chamber question. Please help

Is the barrel free floated? Is the action or barrel bedded?

 

[DedicatedShooter]

Re: Chamber question. Please help

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: longshooter</div><div class="ubbcode-body">Is the barrel free floated? Is the action or barrel bedded? </div></div>

Nope. I paid almost a grand for my rifle to be blueprinted and re-barrelled only to leave the barrel un-floated.

haha just kidding. Heck yea its free floated. I said before that it is in a AICS stock which doesn't require bedding.

BUT I WAS ABLE TO GO OUT AND SHOOT TODAY.

and my best 5 shot group was .403". That was with 175 SMK and 45.0grs Varget with .020" jump. I shot that group with my muzzle brake installed. I'm gonna load up some more of those and try em out next week. I think I'm on to something.