Why?

[eleaf]

As in "Why must the 17 HMR ammo be unsuitable for use in semi-automatic firearms?"

Currently there are 3 beautiful SA 17 MHR rifles at a local gun shop which I'd love to have. I really dig the 17 HMR. Currently it's my favorite rifle in the safe, and a semi-auto sounds interesting and I bet it's fun.

2 Volquartsen rifles with heavy barrels and a third, which I don't recall, that has a CQB-like design and heavy barrel.

I'd love to get one, but with the explicit warnings from all of the manufacturers not to shoot 17 HMR ammo through SA firearms, I'm not getting within 100 yards of buying those things. The only value I can see is buying them as a collectors gun which may be worth something in the future, but, at this point, I'm not all that interested in buying a rifle, especially in a caliber I enjoy shooting, that I'm not going to shoot.

How many of you guys have 17 HMR SA weapons that you fire?

 

[Drumie]

Re: Why?

The last info I heard was that Volquartsen didn't have any issues with their guns. Send them a email and ask them. They usually answer emails very fast. You can't beat a Volquartsen for a semi auto rimfire.

 

[frog5215]

Re: Why?

Apparently, HMR is past the threshold of what is feasible with an unlocked breech, pure blowback action used with balloon head cases.

Rimfires are all subject to slamfires if the case is sticky going in. This is a much bigger deal in WMR and HMR, though not to be ignored in LR.
The bigger problem is the difficulty achieving proper balance of bolt weight, spring resistance, and cycling reliability. Pretty easy with LR, manifest the number of different successful SA .22s extant.
Must be harder with WMR. My own CZ 611 blows/splits cases on several brands of ammo. Ruger pulled the 10/22Mag for such problems, MR ports their barrel in front of the chamber to bleed off pressure.There are lots of guys interested in WMR autos, but no supply at present among major mfgs. Must be some reason, apart from the demand of sub MOA capability to 1K yd at less than $100.
I understand the pressure curve is longer in the HMR than in the WMR, so it's even more difficult to ensure the bolt doesn't open early.
This seems to be the essential problem, case ruptures related to early opening bolts.
Not a problem with the 5.7FN, but that's not a rimfire.

 

[GreatGonzo]

Re: Why?

Also, because of the lack of a locking breach, the 17hmr autos have a tendency to carbon/powder foul at the case neck. If the carbon/powder residue is not taken out it will build up and cause out of battery firing as the case can not fully seat.

 

[SmallBoreSnipers]

Re: Why?

Just want to add my .02 by also saying that the .17 HMR is also my favorite rifle. If there was a Volquartsen in a shop here that I had the money for I'd grab it in less than 2 seconds.