Anyone Here Shoot 7.5x55 Swiss? GP11 FTF

[Triggered]

Recently purchased a Schmidt Ruben K31 straight pull rifle off Gunbroker and made it to the range this weekend to test the rifle out.

Surprisingly, it looked nicer in person than online and it shot even better - but this was to be expected (in theory) with these rifles.

Purchased a 480 round brick of GP11 off of Midway, and I only ran 30 rounds through the rifle at 100 yards, but I had two rounds fail to fire (FTF) which was a little worrisome based on the reading I've done on the ammo.

I can't find any source claiming to have had this issue (I'm sure it has happened), but should I be worried at all? Lot is from December of '84 and the other 28 fired fine.

Few theories in my head to the problem, but curious if anyone around here has comments.

 

[NukeMMC]

Never had issues shooting GP11. Had a Hammerli K31F that shot amazing with it. Sold all my Swiss rifles. Still have some GP11 though if you want it.

 

[ptosis]

GP11 is very reliable, and the manufacturing process (powder, primer and bullet sealing) has been designed for a very long shelf life. I doubt that it is the cartridge. I own 6 or 7 K31s, shoot a couple of thousand GP11 per year, and see *a lot* of it shot around me; the only failures to fire (due to ammo) I witnessed were about 5 years ago with a box of early 1970-s tracers.

I'd rather blame the gun. The most common problem is archaeology -- old grease/oil residue inside the bolt; disassemble+clean+oil+reassemble should fix it.
I have also seen a broken tip of the striker pin on a K31 once, but this is easy to detect. Theoretically, a weak striker spring can also be a problem (it is included in the basic armourer's kit), but I am yet to see it happen in reality.

Hope it helps.

 

[sandwarrior]

Like all things (guns) old, a complete disassembly of the rifle and cleaning would probably help. It was not uncommon to see rifle bolts packed with cosmoline for the trip over. This will dry and dampen the force of the firing pin.

BTW, you didn't mention what the primers looked like. Were they fully dented?

 

[Triggered]

NukeMMC, how many rounds do you have available? Feel free to PM

Remainder of you all...

I am also highly confident the issues I faced were not related to the ammo itself, especially considering the quality of GP11 and its track record.

Primers were fully dented to answer Sandwarrior's question, or looked acceptable to my untrained eye.

I have no clue as to how long ago the rifle was shot or put in storage. Bolt is a little dirty, but did my best to clean it up or may need to strip the gun down further.

Initially I was fearful firing pin spring may have been weak, but the only way to tell is to put more rounds downrange.

Will cut the gun some slack, it is only 74 years old and still shoots quarter sized groups at 100 yds.

 

[sirhrmechanic]

Some of those military primers take a pretty good 'whack' to get them to detonate. So a firing pin with cosmoline or grease (or rust from older corrosive primers), as Sand points out, would be my guess for culprit.

Disassemble the bolt fully. Clean it spotless. Lube with some light oil and try again. Very common in "new to you" old rifles to have old lube hang up a firing pin enough so that it will dent a primer, but not have enough impact to fire it.

I think BuffaloWinter has several Swiss rifles that he posted on the old forum. A couple of beauties. Hopefully he will chime in and re-post the pictures. HIs 'home-made' Scheutzen is magnificent!

Cheers,

Sirhr

 

[buffalowinter]

Hi, I have several swiss rifles shooting 7.5. I've never had problems with GP 11 but it is, afte all, surplus ammo. Everyone offered sound advice and I would not be overly concerned pending a little more shooting with maybe a different lot or different ammo. PRVI makes some inexpensive 7.5x55. Thank, SirH for the kind comments , here, for your viewing pleasure , are some 7.5x55 guns

K-31 Scheutzen, built by myself
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/ZHh6WtPm.jpg"}[/IMG2]

7.5 Hammerli-Martini ca. 1920
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/bjdWErgm.jpg"}[/IMG2]

7.5 Hammerli w/K-31 type action
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/DlRn9cZm.jpg"}[/IMG2]

7.5 Tanner
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/8ETrpL5m.jpg"}[/IMG2]

7.5 k-31 target
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i.imgur.com\/jrEYmAkm.jpg"}[/IMG2]

 

[Triggered]

Buffalowinter,

If I may say, that wood work on the Scheutzen is quite frankly incredible!

The Hammerli-Martini has also struck a cord in me; I would absolutely love to have a 7.5x55 in such a rifle. Huge fan of Martini-Henrys, but they are a little archaic for my taste for not reloading.

Very impressed with your piece, thank you for sharing.

 

[sirhrmechanic]

Buffalowinter,

If I may say, that wood work on the Scheutzen is quite frankly incredible!

.

And since Buffalo is as humble as he is talented at rifle-smithing... he won't point out that he made that stock himself. But I have no such scruples... so I'll say: "He did that stock himself!" Gorgeous, isn't it???

Glad the pictures made the leap back to the new old site. This is one of the best areas on SH!

Cheers,

Sirhr

 

[sandwarrior]

And since Buffalo is as humble as he is talented at rifle-smithing... he won't point out that he made that stock himself. But I have no such scruples... so I'll say: "He did that stock himself!" Gorgeous, isn't it???

Glad the pictures made the leap back to the new old site. This is one of the best areas on SH!

Cheers,

Sirhr

Sirhr,

Too long coming back to this post. So, if I may add, not only is the stock gorgeous, it appears to be quite handy for it's intended purpose.

 

[Wannashootit]

If the round is seated, bolt fully in battery- it's either the primer, or FP related. Could be FP protrusion, or impulse. If it continues, I'd try replacing the FP spring (I've been sent a couple but haven't tried them out yet as I rarely shoot my K-31): https://www.rocksolidind.com/product/swiss-k-31-firing-pin-spring/

They also have a replacement FP, but shows out of stock; if needed suggest you call Ken to see if he's them- not sure if they got past the proto stage on these yet.
https://www.rocksolidind.com/product/test-product-not-for-sale-copy/