.308Win in a K31 Chamber

diopter

diopter

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I was checking out a k31 with W&F diopter that someone could' get sighted in.
Used the trick of using the issue rear sight to set 1000m meters to see how far off the diopter was for 300m.
Was maxed to the right. Centered it based on that, but had no GP11 or 7.5x55 with me.
Range store had some Federal "Tactical" 165gr .308WIN on sale at half price.
Hmmm said my cheap side, why not.
Was 1/2" right at 30yds(indoors).
Recoil was like a .243Win..
Note that the first five rounds fired with no problem in the K31 chamber that still had waffenfett in it.
Next few round were more problematic depending on how the extractor held the rim as the firing pin hit the primer.
Very Interesting. Accuracy was very good.



1984 GP11 at left, .308Win fired in the K31 and right unfired .308win rounds

Do not reccomend doing this on a regular basis.
 
Well that's a new way to get some GP 11 sized brass......

Think you could reload those cases with 7.5mm bullets? The case mouths look a little short to me.
 
diopter said:
I was checking out a k31 with W&F diopter that someone could' get sighted in.
Used the trick of using the issue rear sight to set 1000m meters to see how far off the diopter was for 300m.
Was maxed to the right. Centered it based on that, but had no GP11 or 7.5x55 with me.
Range store had some Federal "Tactical" 165gr .308WIN on sale at half price.
Hmmm said my cheap side, why not.
Was 1/2" right at 30yds(indoors).
Recoil was like a .243Win..
Note that the first five rounds fired with no problem in the K31 chamber that still had waffenfett in it.
Next few round were more problematic depending on how the extractor held the rim as the firing pin hit the primer.
Very Interesting. Accuracy was very good.



1984 GP11 at left, .308Win fired in the K31 and right unfired .308win rounds

Do not reccomend doing this on a regular basis.
Click to expand...

I wouldn't recommend doing this at all. Glad you are safe
 
I was just loading up my gear to go for a LE mule deer (doe) hunt next week, and I almost packed my 7.5 Swiss handloads instead of my .308s. They look very similar; I'm glad I put on my glasses and checked the headstamps!
 
Here is what originally sparked my curiosity to try it.
Note that I did not get any case separation in the K31.
 
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We had a guy at a Milsurp Match get his ammo mixed up and he shot several rounds of 308 in his K31 in one of the relays and it shot as well as the 7.5X55.

Not a big deal - it's much like fireforming Ackley rounds. The COL's of the two rounds are close and so the shoulder and neck blows forward. Being undersized by 20 thou at the base is not a biggie either. Someone will come up with a story that a guy got injured doing that, but it will be hearsay.
 
WARNING..... This should NOT BE DONE. Case seperation at the web can and will occure.
The only thing holding the brass in position is the extractor when the firing pin hits it.
Serious injuries can result from this practice. THIS THREAD SHOULD BE DELETED.
 
First of all, firing a cartridge not intended for the same rifle chamber is not a recommended practice IF you really do not know what you are doing. Many cases can be reformed to give shootable brass from existing cases, giving a usefulness to a rifle for which cartridges have not been made for decades. Other uses are to give better performance.

Knowing DIOPTER, I would be of the opinion that he approached this "experiment" with caution, consideration and forethought. Also DIOPTER is one of the few people who have the knowledge and expertise with the Swiss Military rifles. If we look at this, the bullet is the same diameter so that will not really build up too much more pressure. As the cartridge is fired, it has to travel a bit of a distance forward, thus increasing the area for the powder combustion to occur, lowering pressures a bit. The neck and forward part of the cartridge case are thinner, so will expand to fit the chamber and seal the gas.

Of anyone thinks about it, some semi automatic rifles chambered for full powered cartridges have grooves in the chamber walls to aid extraction, so probably seal not as well as a smooth chamber wall. As mentioned, the Ackley cartridges are blown out and have a shoulder blown forward.

As far as the web at the base, the .303 British is famous for developing inside web cracks and leaving a part of the case in the chamber. This generally occurs after several firings and full size reloadings but it takes time. Anyone who has fired a ROSS with an enlarged chamber is familiar with expanded bases and as far as the short necks go, how many of us have picked up .303 Savage cases on the range that were fired in the .303 British?

There is still enough of the neck to seal the chamber. Ignition would be a factor but maybe SMELLIE's trick with the .303 might work. That is, a small rubber "hair" band or "O'" ring slipped onto the base to hold the cartridge back against the face of the bolt. It works well with the .303 but that cartridge has a very positive rim.

So, I would take DIOPTER's experiment as just that ----an experiment. Anyone who wants to duplicate it has to consider his own actions, rifle condition, ammunition, and other factors, and is responsible for those actions.
 
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