STG57

[Patrick Chadwick]

...still sounds like an overall length thing, bullet in LEAD or commencement... t...

Hallo Ovidio, I agree with Jim. It is not sufficient to rely on OAL for really precise bullet seating. Variations in the ogival curve between different types and (on the sub-tenths of a mm level) maybe even between batches of the same bullet will affect the precise seating depth at which the bullet contacts the transition cone a.k.a. throat.

I suggest that you take a couple of your reloads, ink over the contact area with a felt pen, and load/unload them in the rifle by hand. If there is any marking of the inked area, then you know that your bullets are touching the lands. All mechanical processes - bullet manufacture and bullet seating - have tolerances, and if the bullets are too close to the lands (which in my view is anything under 1/10 mm) then some will be touching, some will be free, and the variations in pressure will affect the grouping.

My guess is that if you seat the bullets to be at least 0.25mm off the lands performance will be improved.

Give it a try!
Patrick

[browningautorifle]

I suggest that you take a couple of your reloads, ink over the contact area with a felt pen, and load/unload them in the rifle by hand.

Yep...that's what I'm thinking too. You will likely feel them touching the commencement anyway, they'll stop hard before they should. Too, bullets that touch the commencement have a higher pressure at firing...so I understand.

By the way, I think it's leade not lead at the commencement...someone will correct me I'm sure...

[Ovidio]

Thanks guys.
I’ve been in Germany the whole week and will be back home tomorrow evening.
All the time with that thought nagging at me. I really want to understand what happened.
But Saturday, after showing the company to a few Austrian customers, I’ll go with my heir to the range with our old Carcano and the Persian Mauser. Fass will be nect week again.
But I’ll update you.

[Ovidio]

Finally I remembered to take pictures of the infamous round that got stuck.
It is not dented at the shoulder, so it really got blocked before completely chambering.
The striker touched the primer with some authority, not enough to get it going, luckily.


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[browningautorifle]

Can't help but say it has to be too long. The mechanics speak for themselves. It needs to be shorter so the bullet doesn't touch commencement. The shoulders of the case don't look sharp either, like this hasn't been sized...but I can see your trim marks at the mouth.

[Ovidio]

Fact is, I sized, trimmed and chamfered each round. Then I use a manual scale and also put the powder manually in each and every round.
After seating the bullet, I measure again each and every round, allowing a maximum of 1/10th of a mm of tolerance.
That's the reason I decided to put everything aside and keep shooting with the Mauser.
I really could not understand how a problem like that could have occurred.
And, sincerely speaking, I still don't get it.
The shoulders have just touched the chamber. It can be seen, but it is miles away from the way the other cases look like after being simply chambered, let alone fired.
Someday I'll take her out again and fire the commercial S&B rounds. They have the exact same length of mine, but the brass is new.
Let's see...
Luckily I don't fret about semiautos.

[Ovidio]

I got the field manual of the Fass57 from a Swiss guy who writes on our Italian Milsurps Forum.
Interesting.
I also found the complete German manual.

Now you guys have an excuse to start learning Dante's magnificent language. And Goethe's!

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[Bruce_in_Oz]

What bullet were you using?

GP-11 ammo has an "unusual" bullet that has a VERY short parallel section and the ogive is a Secant type. Thus, it starts decreasing in diameter immediately in front of the neck of the case.

When I bought my K-11, the only GP-11 ammo around was "collector" ammo, no bulk shooting ammo around, here in Australia. It is still hard to find in shootable quantities at a realistic price.

So, I loaded up a few cases with Sierra 155gn Palma Match bullets that I used in my .308" Win chambered target rifle. So far, so good.

It got interesting when I passed this information on to a friend who had bought a K-31 from the same collection.

Next thing, he asked if I could come and look at a "problem". He had made up some dummy rounds for testing and now had a bullet stuck in the leade.

The K-11 has a LONG leade to accommodate the older GP-90, round-nosed bullets that were the standard until 1931. So, The K-11 has a long leade, even though it was introduced with the GP-11 with its MUCH more streamlined bullet.

Thus, If you are loading for a K-31 or a PE-57, you need bullets with a SECANT ogive, like some of the Hornady bullets, exotic "VLD" types or, in my part of the world, the Australian -made BJD 155 grain HBC .308" target bullet. These also work fine in the long leade of the K-11 but have a fairly long bullet "jump".

Can you get GP-11 projectiles from Switzerland for reloading?

[CINDERS]

I gather Ovidio when you resized it was FLS'ing the cases and not just neck the only thing I could think may have happened is you short stroked the press by a phhhhtinth of an inch (Less than a gnats fart) and it has not bumped the shoulder back causing the shoulder to be forced into the chamber but keeping the weapon just out of battery. If all the other cases worked flawlessly then this one well perhaps just missed out and having the projie come out in the lede implies the COAL is to long I would use a dummy round loaded to what you did previously and soot the projie with burning camphor (Mothballs don't do it inside it will soot your nice white walls it arcs the wife up bloke) then very carefully single load it and close the bolt reasonably gently on it then carefully extract it. If it again sticks in the bore then load the projie again put a comparator on it adjust the COAL by 2-4 thou and go again until you get the marking just visible on the ogive I would then give the projie a 30-40 thou jump (Well decrease the OAL by that) and see how that goes. The comparator (Or a Comparator nut if you have one is the way to go to much variation measuring from the meplat.)

You may find the accuracy gets better as all of the rounds may have been slammed into the lede causing mis-aligment of the projie to the bore and a crooked bullet wont fly that straight.
I may be completely off course but thats what I am taking away from this

[Ovidio]

Hi Bruce, thanks for this very interesting information.
It seems he had the same problem I experienced at the range.
I was using plain and simple Hornady HPBT 168 grs. bullets, and they surely are not with secant ogive.
In the pictures attached you see the Hornady bullet in the middle.
Left is a new monolithic 160 grs. bullet for long range shooting, from a new Italian company (I'll try them in the K31 and M1917), and right there is a classic S&B FMJBT 180 grs.
I also have the 147 grs. S&B. Similar profile, just shorter.
Looking at the shape of the bullets, maybe the monolithic could be ok.
In the K31 I never had trouble with the S&B bullets. I still have to try the Hornady, but I don't think there will be any difference, as they are pretty similar.
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