22lr bulged cases

[targetfire]

Hi all, a friend of mine has a Unique single-shot french bolt 22 lr rifle. The gun is has about 35 years. It shoots very accurately, but some cases has a little bulge around the firing pin. This happens only 30% of rounds with some ammo brand (other ammo does not bulge) and after hundreds of shoots there are no splitting cases.



The left one is the bulged case.

The firing pin hole appears to be slightly oversized. Is this the cause of the cratered brass?
I must say that the case shown in the image above is the most bulged of all. Others cases are only slightly cratered.
This happens only with some Remington Thunderbolt and one brand of Winchester ammo. Other brands (RWS, Fiocchi, Winchester, etc) does not show bulge.

Is this dangerous?
Our Gunsmith saw many cases and he told us that this little bulge is tolerable, but Various expert opinions are better than only one.

Thank you very much!

 

[Afy]

I am very familiar with Unique. Their firing pins are larger than normal, and from what I know so is the spring. This is from a person who owns four of their rim fire's. (not me, I only have a CZ)

Normal for the Unique's to be this way.

They were recently acquired by FMR and are now known as Unique FMR, and do a number of custom builds as well.

 

[targetfire]

Thank you for you observation Afy. I don't know the exact rifle model, but it is very old and is very accurate and reliable. It is a great rifle! We enjoy shooting it.

Best regards!

 

[Afy]

BTW a Unique .22 LR single shot, can set you back about 1500+ Euro's.

They are expensive rifles... FYI.

 

[Stevie-Ray]

This happens only with some Remington Thunderbolt and one brand of Winchester ammo.

Would that Winchester be the Wildcat? If so, it probably happens only with hyper-velocity cartridges, and not standard-velocity. The hyper-velocity is usually crap for accuracy, anyway.

 

[targetfire]

Hi Stevie, the Winchester brand is the Laser (I think hyper velocity) and you're right... from this rifle the standard velocity ammo is the most accurate.
Regards.

 

[TimboKhan]

Of course these guys are right! Your new here, so maybe you don't know this, but we THR guys are the smartest guys in the world, and possibly ever!

Seriously though, welcome to THR! I have never even actually heard of Unique rifles, so it was interesting for me to look them up and see what was what about them.

 

[rcmodel]

This happens only with some Remington Thunderbolt and one brand of Winchester ammo.

Then don't shoot Remington Thunderbolt and one brand of Winchester ammo.

There, that took care of that problem!

rcmodel