Bulged 17HM2 cases?

[IdahoMike]

Iam going to but a 10/22 barrel in 17HM2, I had emailed Shilen with a question and they told me that they arent making the 17HM2 barrels because of problems with ammo manufacturing?

I also heard that the reason there had been problems with the HM2 barrels had something to do with the chamber?

Can someone clear this up for me?

 

[donws2]

Re: Bulged 17HM2 cases?

I've blow a couple case heads on the two I built. One was a E R Shaw barrel and bolt handle and the other is a Green Mountain Barrel and E R Shaw bolt handle. I've purchased a Bolt handle assemble from Rim Fire Technoligies but have not used it yet. I have heard of two things that could be goin on.

ONE is the bolt handle does not have enough mass/weight to operate the HM2 as a blow back. A stronger spring would help but is not the correct way to fit the problem. I think a tungsten bolt handle and or a bolt body would be perfect. If you ever get a chance check out the bolt on a Sten. It's a blow back 9mm Sub Gun and it weights almost 2 lbs.

TWO is carbon build up in the neck can lead to higher pressure. There is merrit to this as the same problem is known to happen in M1 Garands and M14 rifles. Both are bottle neck cases even though they are lock breach designs carbon is a killer if on cleans out of the chamber.

The only problem I've concured so far is the feeding issue. I had to lower the rear of the mag and raise the front so the bullet would feed in to the chamber correctly. The bullet tip just impacted the breach face and jammed before I mod'ed the mag aliitle. I have not done any more on the case head problem and most likely want until the weather warms up and I can spend the day at the range and not freeze.

Not much help but still info is info. Donald