Time to pick some brains...

[284STW]

Ok, I've posted this on wssmzone.com as well but figured being as there's plenty of gun savvy folks around here I'd ask here as well. I recently aquired a win mod 70 super shadow in 223 wssm. I got it for a good enough deal that I'm not worried if all I end up with is an action but would like to use it as is for a good coyote gun to keep in the truck. These things come factory with a 1 in 10 twist barrel. The gun wasn't shooting good so I started chasing the usuall suspects. I've don the following:

Bedded recoil lug, wasn't touching at all

Tried a proven scope, changed to better scope mounts

floated the barrel

tried loads in 40, 55, 60, 64, and 68 gr bullets.

bore scoped barrel, looks good enough for factory

cleaned all copper.

This thing still won't shoot. Today was the first I've got to shoot it after bedding. The rifle was still extremely inconsistant. Seems like some of the bullets never reached the target. I got to messing with it and found that some of the bullets were coming apart right out of the barrel. These were 60 gr bergers and 68 gr wildcats. This was occuring at velocities ranging from 3200 to 3500 fps. Anybody have any ideas? Could there be some kind of inconsistancy in the bore diameter causing this? There are too many folks out there that wan't to hate on the wssm's for one reason or another. All prejudice aside, there must be some mechanical reason for this happening. Plenty of folks out there are having luck with this round. Any insight would be appreciated.

Thanks in advance. /ubbthreads/images/graemlins/confused.gif

 

[James Jones]

If you had the bore scoped and it looks good I have to ask was it scoped the whole way through? I have heard of barreld that have had the lands "missing" further up the barrel of had bad spots further up.
My next guess would be to have it recrowned , it only takes one little booger that you can't even see to ruin accuracy

 

[284STW]

He ran the bore scope in from both sides so with that 22" barrel it easily covered it. I didn't look at the whole thing but my gunsmith did. I do trust in his abilities as he seems to make some awesome stuff and pays very good attention to detail. I figure if there was anything that obvious he probably would have caught it but then again anyone can have a bad day. The crown actually looks pretty good on it. He even commented on it being pretty good for a factory crown. I agree about crowns as well, I'm kind of obsessive about them, usually don't trust a factory crown and always figured it's the best 40 bucks a person can spend. I have noticed that all my brass is probably a little tight on the neck inside diameter. It measures .220 after re sizing. Could this cause the bullets to explode? I know the seating pressure is more than it probably should be as the seating die leaves a very slight ring on the nose of the bullets. I have ordered a Forster neck turner and also a reamer to use in my trimmer. But I've even had some of the factory loads come apart as well so that would have to be occuring somewhere other than in my re sizing die I figure.

 

[lazylabs]

Have you tried any factory ammo?

 

[284STW]

Yup, no luck there either. Probably less of them dissapear before they hit the target and there is no real consistant pattern of where they hit.

 

[Mikecr]

Are you sure it measures .220" after sizing?
What does it measure right out of the chamber?

Doesn't make sense.. The brass is ~.020" thick at the necks..So .220" - .040" = .180" ID
.224 -.180 = .044" of neck tension!!!!!!!!

You'd be half destroying the bullets with seating alone.

I'd expect something like .224 +.040 - .002 for .262" loaded necks.

 

[284STW]

Sorry, should have specified brass measures .218-.220 id after sizing. Just measured factory loads fired .220-.222!
Reloads fired all measure .224+. Is that thick brass getting some kind of spring back? Expander ball in the die measures .221.

 

[Mikecr]

Referring to ID of necks is strange for sure.
You apparently don't need to neck size the fired factory brass until after the second firing. I can tell you neck tension takes on a new meaning with brass this rediculously thick. Use as little as measurable(it will be enough).

Personally, I'd pick up new Win brass rather than reloading factory.

 

[284STW]

Half the reloads I just fired were actually new ww brass. I'm thinking of reloading some that measure for very little neck tension and seing what that does. I have made up my mind that I'll probably scrap the barrel and stock anyway. Just can't be happy with a round with the velocity capability of that rifle having a 22" barrel anyway. That brings me to another question, anyone have any suggestions for barrels as far as groove and twist? I understand twist rates fairly well but making a decision on grooves I have nothing to go on. What kind of difference does it make? What I've got in mind should make a fairly decent long range coyote gun when I'm done with it.

 

[rotorhead]

Ok Hear is the problem, I have worked with several of these **** wssm's well I shouldn't say that because once you figure out what the problem is you can fix it. The only brass available is winchester the design is a thicker than normal neck material this will give more tension alone. If your sizing die is bringing down your neck to much get a bushing die. The real problem with the wssm's is the brass is to **** hard anneal your brand new brass and alot of your poblems disapear. Hope this helps

RH