7.5 x 55 Swiss Collet vs Full Sizing Die

[Duster340]

Hey folks,

Gonna start loading for a K31 project I recently acquired. Got brass, bullets etc. Need to order a set of dies. Leaning toward the collet sizing die set. I use one for all my 303 Brit needs with great results and long case life. Any reason to get a full length die for the 7.5 Swiss? I'm guessing the collet only set would be fine given I'll only use the rounds in this one rifle. But figured I'd throw the question out there just in case.

Thanks!

 

[Proinsias]

What brand die, and what brand ammo? I've only reloaded a few 7.5x55 rounds, with a FL. But it's a kind of picky caliber to reload - had to go with a dummy round to pass through a few times as a prototype.

 

[rjbmjb]

I load for my K31 using a full length sizer with no problems. It's a great rifle- my son can almost drive nails with it at 100 yards (my old eyes won't let me get that close). From what I have read, collet sizing can improve accuracy and extend brass life, since the brass is not worked as much as with FL dies. Since the biggest variable affecting my group size is the shooter, I wouldn't be able to judge the accuracy issue, and I don't shoot it enough to worry about brass life. All that being said, since you are only loading for one rifle, I don't know any reason that the K31 should be any different from your 303. I bought my dies before I learned the difference between FL and collet sizing. If I was starting out today, I would probably opt for the collet die.

 

[mustbe]

I've been shooting a K31 in vintage for about 15 years. I started with Graf brass and a Hornady FL die. The Hornady die is specific to the 1911 and not correct for the K31. The brass started to split at the shoulder after about 5-6 loadings.

Due to the straight pull action the K31 lacks the camming effect to force a round into the chamber. It's very picky about proper sizing.

I now use a lee collet for about 3 reloads then anneal and FL size with a Redding die made specifically for the K31.

I've lost track of how many loadings I have on my last batch of brass but this method seems to work very well and extends the brass life considerably. Plus, the collet die is fast and effortless.

 

[Duster340]

What brand die, and what brand ammo? I've only reloaded a few 7.5x55 rounds, with a FL. But it's a kind of picky caliber to reload - had to go with a dummy round to pass through a few times as a prototype.

Thanks for the reply.

LEE Turret Press
PPU cases
PPU 165gr SPBT

I typically make dummy rounds to ensure they cycle. Will do it with I intial loading with new brass and again when loading up fireformed brass.

Thanks

 

[Duster340]

I've been shooting a K31 in vintage for about 15 years. I started with Graf brass and a Hornady FL die. The Hornady die is specific to the 1911 and not correct for the K31. The brass started to split at the shoulder after about 5-6 loadings.

Due to the straight pull action the K31 lacks the camming effect to force a round into the chamber. It's very picky about proper sizing.

I now use a lee collet for about 3 reloads then anneal and FL size with a Redding die made specifically for the K31.

I've lost track of how many loadings I have on my last batch of brass but this method seems to work very well and extends the brass life considerably. Plus, the collet die is fast and effortless.

Thanks mustbe. Great info. Didn't think/know there was a difference in the FL dies for the K31. This kind of insight is why I come here!

 

[Galil5.56]

I use Redding FL dies for my K31, as it is also my understanding, they are made to the proper chamber spec for the K31. They work very well, and using them is a pleasure. For me, it was definitely worth the extra $$$.

 

[Slamfire]

Don't neck size or collect size for this rifle. As Mustbe said, this is a straight pull rifle and it lacks the camming of a turn bolt:





You stick a case in that gun and could damage that bolt bar getting it out. Good luck on finding another. There are complete bolts on ebay, don’t count on them being around forever.

The greatest problem I had was there the lack of Wilson type cartridge case head space gages. Recently, PTG made chamber headspace gages available,

http://pacifictoolandgauge.com/cip-...5-x-55-suisse-swiss-cip-headspace-gauges.html

but, I have not found a Wilson type cartridge headspace gage. I ended up using what is now called a Lock-N-Load® Headspace Comparator https://www.hornady.com/reloading/precision-

I measured the base to shoulder distance of a fired case and bumped the shoulder back about 0.001” to 0.003”. I have flawless feed and extraction.

In an old bolt gun match, I did this offhand at 100 yards with my K31!



Just bursting for a bayonet charge!

 

[Duster340]

Thanks for the great input. The rifle was given to me by my brother and from what he said, is crazy accurate. All matching, great bore, but stock was "sporterized" in the past 60-70 years. The more I research the K31, the more geeked I get about owning and shooting one! This one will accompany me next deer season.

 

[Whiterook808]

I full length size with Lee dies, which work well for me. I find that in my rifle COAL must be shorter than listed in some manuals, such as Hornady. Be sure that your bolt can close all the way.

I am solving the 'old eyes' problem by using the St. Marie clamp on scope mount. Today I just mounted and bore-sighted a Redfield Revolution 4-12x40mm on my K31. I hope to get it sight in next weekend. Since this does not alter the rifle, I can just remove it to restore it to the original configuration. Also, the irons are co-witnessed.

 

[Grumulkin]

Collet dies probably improve brass life but they DON'T necessairly improve accuracy. I quit using them.

It's also more likely than not that eventually you'll have to full length size to get the cartridges to chamber easily.

 

[Slamfire]

All matching, great bore, but stock was "sporterized" in the past 60-70 years.

Unless it was sporterized in Switzerland, it probably was sporterized since the mid 1990's. It is my recollection that the first K31 that I saw was a private sale to an American. (Rifles sold to Swiss citizens have a tang stamping.) And that American sold me that rifle at a gun show in 1997. I paid $350 for that rifle, because the things were rare. My timing was impeccable as usual, as shortly afterwards, K31's were selling for as low as $75.00 a rifle, for a scratch and dent version. A bud at work purchased a couple of those. Still I was able to score a couple of very nice ones for less than my first one. Prices have since gone up.

It is my recollection that the earlier models, such as the Swiss M1911's were imported in the US in the 1960's, that is when I remember seeing them. But the K31 was a rare bird until recently.

If you reload, I recommend a 175 grain bullet and any of the 4350 powders. I am using WC852, which is a surplus military ball powder. Accurate Arms makes a copy called AA2700. It is a good powder in this caliber, provides service rifle velocities at mid 40's psia pressures. This round is powerful, my reloads push a 174 at 2550 fps or so, that is the equal of the 308 Win any day.

I took one of my K31's to CMP Talladega, it sort of held the ten ring at 200 yards, held the nine ring at 300 yards. Only after I was done and cleaning the thing did I find that I had not tightened the stock screws. Opps! I loosen the things on rifles I have not glass bedded and am not shooting. There is no good reason to compress the wood. The Range Master had a story of "some cocky kid" who brought one out, and proceeded to show all observers why he was so cocky. Like Dizzy Dean said : "it ain't bragging if you can do it!" The kid shot well with his rifle all the way out to 600 yards and impressed the Range Master. That's a good recommendation.

 

[Proinsias]

Oh yes, forgot about 1911 vs 1931 dies. The more expensive brands like Redding say they're 31 specific, but that doesn't meant that the cheaper brands are

If already sporterized, I guess mods don't matter as much, but if you still want to scope it without damaging anything, the Swiss Products clamp on mount works good.

 

[Whiterook808]

I agree on the 4350 power. I use IMR4350 and it seems to work well for me. I tried 4064, but not so good.

 

[Duster340]

I'm hoping to utilize IMR 4895 and/or IMR 3031 as I have plenty on hand. Hopefully I can work up some nice loads.

 

[Random 8]

I've been reloading the 7,5 for about 14 years for competition. I shoot my rifles in CMP vintage matches, as well as reduced course (300 yards and 300m E targets NRA OTC with diopter sights). I also shoot 300m Swiss matches, but these must use GP-11 issued at the match so reloading NA.

I own the LEE collet set, and a Lee FL set (1911 dimensions). I load almost exclusively on the collet dies, and mark the lots of ammo per rifle. I have never had a problem with extraction or chambering. I do use the FL dies for converting brass to a different rifle, and for ammo to be used in a rapid fire string. I get fine accuracy with either, no noticeable difference. Brass life is phenomenal with the Collet dies. I have to call it infinite as I haven't tossed any yet after more than 10 firings. I get about 8 firings with a relatively mild load and the FL dies. I do set them short on my dedicated K-31 ammo so I'm not getting a full shoulder bump. I'm using PRVI brass.

PS, for shooting at or under 300m, try the Nosler 155 BTHP or Nosler 150 BT (hunting) over 42.5 gr IMR 4064. Mild recoil, extremely accurate in all my rifles, approximates 7.62 NATO M80 ball ballistics. Pay attention to your COL. Most manuals list a COL for M1911 type chambers which is FAR too long for the K-31. You want to insert an unsized case with a bullet lightly tensioned in the neck with a little tape adhesive (remove the tape, just leave some of the sticky behind). Fully chamber, then carefully extract and measure. This will get you your zero freebore measurement. You want to seat a few thousandths short of this. Verify with your loaded rounds blackening the ogive and looking for rifling engraving marks.

 

[Random 8]

I'm hoping to utilize IMR 4895 and/or IMR 3031 as I have plenty on hand. Hopefully I can work up some nice loads.

Of those 2, I would concentrate on the IMR 4895. Think of the 7.5 as a 30-06 in terms of powder burn rates. 4895, Varget, 4064 for 168 and less, 4350 for 165 and heavier. I have also used VN140 and Varget with good luck in both the K-31 and Gew11 with bullets of 155 and 168 grains. I am a fan of the 150-155 weight due to the K-31s short leade and the low-recoil and accurate loads they produce. Unless you're hunting game larger than deer or shooting extreme range, they will do nicely. Bullets with a "sharp" ogive such as the BTHP match bullets, or lighter bullets are generally needed to seat short enough without being excessively deep in the case. A flat based 150 spitzer should be an accurate deer hammer and can be loaded to the cannelure and still have a COL suitable for the K-31. I have used the 150 Hornady flat based spitzer and this was the case. Have not hunted with the Swiss rifles, but have taken numerous deer with this bullet at similar speeds.

 

[Duster340]

Thanks for sharing the info with me Random 8 much appreciated.