The 7.5x55 Swiss

[yodar]

Re: CB in 7.55 Swiss. I am still skeptical at my friends' assertions the the Lee 312-155-2R will work in light of another casters view that the bullet has to read .301" 0.17" up from the case mouth to fit right (it doesnt). I've about decided to use the little 134gr 311410 from Lyman which you see here in my .30 carbine loads.

It DEFINITELY wont hit the chamber mouth ;>)

[35 Whelen]

As always, excellent post, Bob. I've just ordered another K-31 from which I intend to build another High Power rifle. I'll definitely try the bedding techniques you described.
35W

[FAsmus]

Bob;

Thanks for the comprehensive information on the K31s bedding system. You have addressed all points of my curiosity about why it was made as it was in the first place and how to go about tuning it up to shoot as well as possible. Wonderful stuff.

I have a certain interest in shooting this rifle in the CBA Postals "As Issued" and so will follow up on the armory’s version for making the system work as intended. This may take some time but, I got the rifle with the intention to learn about it according to its design, not to hammer it into my own idea of "proper" as per a standard Mauser type epoxy job and your information will make this possible.

Good afternoon,
Forrest

[rvpilot76]

Bob where did you get that stock? I've got a K31 on the way, and I'd like to turn it into a match rifle very similar to what you have there. Which sights have you got on your K31? Any other details about your K31 that you'd like to share?

[Bob S]

The rifle pictured is a CISM rifle (300 Meter Standard Rifle, repeater, also called an "Army Rifle") that was built by Grunig and Elmiger around 1969. The action started out as a military carbine manufactured in 1954. When I bought it, it was missing the bolt, magazine, rear sight and buttplate, so I got it for a song. It is chambered in 7.62x51 (308 Win) The wood looked like it had been bouncing around in the back of Bubba's pick up truck. I had all the parts needed to put it back on the firintg line. The rear sight is a PNW.

Sadly, no one that I know of currently makes any aftermarket stocks that are suitable for match rifles. Boyd's made a duplicate of the military stock and a "sporter" stock, but they are no longer made, or they are made in infrequent "limited runs".

Resp'y,
Bob S.

[35 Whelen]

Boyd's made a duplicate of the military stock and a "sporter" stock, but they are no longer made, or they are made in infrequent "limited runs".

FYI, I checked Boyds site and they show the military stock and handguard as does Nurmich up in West Hurley, NY. I wish someone made a "beefier", target type stock, but doubt that will ever happen.
35W

[FAsmus]

35W;

Your pictures, with loading notes included, show what I would call in my own loading terminology "squib" or very light loads.

How did you arrive at these? In other words, did you test the typical levels of 4759, 4198 or Varget and find them lacking compared to the light loads of Bullseye?

With just the 80 rounds tested so far in this Swiss I have seen several groups in the area of 5x1.500 , 5x1.680 and so forth shooting 20.0 grains 4759 under the RCBS 30-150-FN .. This bullet gave best results ( I think ) because it is a 30/30 design, casting at 0.3090 x 0.3000 - and I shoot them as-cast.

I have not tested things like a Coaxisized 311284 yet since the bedding seems of primary concern at the moment - but I intend to do so.

One of the things we do here at my place is shoot at extended distances - once a rifle & load is proven at close range the usual next step is to move on out to 350 yards (our closest and "offhand" target) and by 10 steps to 834 yards. I hope to shoot the K31 out that far by the end of summer even though the lack of any windage in the sighting system will cause a certain care when I select the conditions on any particular day.

As I doubt 10 grains of Bullseye would carry that far - I'm interested.

Good evenig,
Forrest

[35 Whelen]

Your pictures, with loading notes included, show what I would call in my own loading terminology "squib" or very light loads.

How did you arrive at these? In other words, did you test the typical levels of 4759, 4198 or Varget and find them lacking compared to the light loads of Bullseye?

First, I was given the NEI mould from which my bullets are cast. I realized right away that this mould cast good, consistent bullets. Since the bullet is a plain base design, I also reaized that velocities would need to be kept low. I'd read C.E. Harris' article on cast bullets in military rifles, so I started with 7.0 grs. of Bullseye and 8.0 grs. of Red Dot. Both loads shot fairly well, but the Bullseye load seemed a little better. After a match or two and some less than satisfactory results, I decided the problem might lie in the fact that my bullets were making the transition from super-sonic to sub-sonic before reachng the 100 yd. target. So I backed off the Bullseye load until my MV was sub-sonic, or right at 1100 fps. At the same time, I came to the realization that all that is required is that I poke a hole in the target. There are no extra points for burying a 25¢ MatchKing 3' into the backstop. This epiphany further fueled my desire for lower velocities.
My goal is to get my Expert card, then wring out my current load as best I can before moving to something faster. If and when I shoot at extended ranges, I'll switch to hotter loads with gas-checked bullets.
On a side note, Monday I did a little experimenting with AA5744 and jacketed bullets in my K31. With 20 grs. and a Sierra 155 gr. Palma, I got a 5-shot group measuring 1.1". Ten hornady 150 gr. FMJBT's with the same load grouped into 1.75". Thst should hold the 10-ring on an MR-31 target. I already know that the rifle will group GP-11 into less than 1.5" @ 100 yds., so I have that to fall back on if/when I shoot at extended ranges.
FYI, the cast bullet benchrest guys run their bullets at about 1700-1800 fps and shoot at 200 yds.
35W

[Bret4207]

Excellent thread gents! 35- I missed that those groups were PB, fine shooting!

BobS- As usual your post was extremely well done. Sure wish we could pick your brain more often.

[Calamity Jake]

35W;

I hope to shoot the K31 out that far by the end of summer even though the lack of any windage in the sighting system will cause a certain care when I select the conditions on any particular day.

Forrest

The front sight is adjustable for windage, it sets in a dovetail that angled across the barrel, moving it forward moves boolit impact the the left.

[Bob S]

35W;


even though the lack of any windage in the sighting system will cause a certain care when I select the conditions on any particular day.

Good evenig,
Forrest

I'll repost the windage adjustment instructions later ... can't access Photobucket from the DC office

Resp'y,
Bob S.

[Bob S]

I'm going to be real lazy and just link you to it.

http://collectorguns35625.yuku.com/topic/3467


Hope this helps ...

Resp'y,
Bob S.

[FAsmus]

35W;

Roger your load developement information.

In my CB shooting I have departed from plainbase shooting except for all the shooting of "Buffalo Gun" calibers that I do.

In this type shooting GCs are of no use due to other considerations that affect the accuracy and long range perfromance of a given bullet design. One of these factors is the transition from supersonic to subsonic that you have mentioned: It is advantagious to shoot subsonic loads if possible since the trans-sonic portion of the bullet's flight is where the most induced drag is imposed on it and, thus, the most wind-drift .. this is one of the underlying reasons the blackpowder boys do so well at long range; thier BP loads seldom achieve supersonic speeds and benifit from typical single digit standrad deviations.

~ Anyway, I got it.

In my initial load development with the Swiss I stuck with standard GC levels of 4759, and 4198, with only one try with Varget since my supply is low and there is no more avialble around here.

I have not had the time recently to follow up on the bedding of my K31 as outlined in this thread due to getting prepared for the local 1000 yard Championship (tomorrow!) but when this match is complete I'll be putting the Swiss project #1 on my loading bench and keep this thread alive too.

Good morning,
Forrest

[FAsmus]

BobS:

I went to the site you gave us - thanks.

In the long range games I play it is a "given" that we use the adjustable front sights as produced by Montana Vintage Arms since the usual rear sights do not have the capibility to compensate for large windage corrections at times; windage needs sometimes exceed 30 minutes in this sort of shooting.

The angled dovetail in the K31 sighting system is easy to understand ~ but of course it isn't intended to be adjusted on the firing line as conditions change during a match!

I would be quite interested in buying one of those adjustment tools though. Where could a fellow get one?

Good morning,
Forrest

[legend]

i have thought of useing a "nutsplitter"on mine i just havent yet...

[462]

One of the Swiss rifle sites has information on homemade K-31 front sight adjusters.

One of them utilizes a nutsplitter, as legend mentioned. Another uses a shaft stop -- 1 1/16" diameter, I think.

[Bob S]

Good evening Forrest,

The only shooting I have done with the K31 and as-issues sights is the CMP course at 200 yards, or the same course at 100 yards on reduced targets. I have sometimes used cast bullets, but I most shoot jacketed loads using salvaged bullets, powder and even primers (yes, primers) from old Navy A-190 300 Win Mag ammunition. The cast loads are very mild and would not be suitable for much beyond 200 yards and even the jacketed loads I use are pretty mild. I can use the Swiss front sight adjuster during a match: I can manipulate it with one hand without disturbing my NPA, and make precise changes. It is not as convenient as twiddling a knob on a Warner sight, or a Soule sight or even windagauge front sight. My MO is to get centered up for the average conditions using the sight adjuster, and then take favors if required by a condition change significant enough to move the shot out of the rather generous ten ring that we use (7" on the SR target at 200 yards). Those who shoot the Swiss GP-11 service ammunition, or equivalent handloads, will probably never even have to take favors after getting centered up, as any wind that will blow the bullet out of the ten ring at 200 yards is likely to blow the shooter over first. (That's only a slight exageration .)

IIRC, and I freely admit that I have not looked at the CBA rules in ages, for the "military rifle" class, you can use modified sights and stocks, but you are restricted to an "issue" barrel? And the shooting is all at 100 yards, or at least not over 200 yards? If that's still the case, I can highly recommend the Swiss Product target sights that are sold by Graf's. They are not cheap, will cost more than the rifle cost you, most likely, but they are a true match grade sight set, and they require no permanent alteration to the rifle: they simply clamp on. If scope sights are allowed, I also recommend the clamp-on scope mount. also available from Graf's.

For your cast shooting at the longer ranges, I think you're going to need something a little more powerful than what I have developed with cast. I have on my "to do" list to try the Ideal 311334. I have two moulds, and they are poor performers in most "conventional" .30 cal. barrels because the noses cast at .298 from both of my moulds. That should be perfect for any of the Swiss barrels. Based on my US Cal 30 experience, I would try the case full to the bottom of the shoulder (top of the case body) of 4831. You could also try Larry Gibson's load of 26-28 grains 4895 with Dacron.

Even if you are successful in finding a load that shoots acceptably well at ranges past 300 yards (and I am certain that you will), you're going to need a rear sight (or telescope) with sufficient precise adjustment in both elevation and windage. The elevation steps on the issue rear sight are way too coarse, and you can't get the magnitude of windage adjustment that you may need by moving the issue sight, even if you do get proficient with the little screw tool.

I am currently using a John Wilkes rear sight on one of my K31's, and I am convinced it's the best option out there for anyone who wishes to shoot longer ranges with cast bullets in a K31 and does not mind drilling and tapping the receiver. It has a huge range of adjustment in both elevation and windage.







The small Swiss sight adjusters can be found occasionally on eBay; or you can go to swissrifles.com, and PM or email the gentleman who posts there as "Guisan". His name is Frank Binnendijk and he is in the Netherlands. But his prices are reasonable, and delivery is unusually fast. I guess the Dutch Pony Express is faster than ours!

Resp'y,
Bob S.

[Bob S]

More sight adjusters:

The Monster:



This one was used by the armorers to install and zero the front sight. When the windage was zero'd, the front sight was staked, sometimes very heavily. This tool is obviously not very convenient for range use, but sometimes it comes in handy to "break the stake", so that one of the more dainty and range-handy adjusters can be used.

My first improvised front sight adjuster. This one also will "break the stake", but it's a helluva lot cheaper than The Monster above (which probably cannot be found on the market anymore, anyway). Less than ten bucks at True Value, some grinding, and you supply the combo wrench from your tool box:





Bob's Precision Elevation Adjuster, Mark One, Mod Zero:





This is simply a relatively fine thread socket head set screw. A spare K31 sight was drilled and tapped to receive it. The length of the screw was "tuned" so that the screw is just out of the line of sight when the sight leaf is at minimum elevation. The screw length and thickness of the sight leaf gives sufficient travel for over 1000 meters with the service ammunition. I filed a small notch in the head of the screw and marked it with paint to give a reference point. Keeping track of the number of full and fractional turns made it possible to make repeatable adjustments to within one MOA. Fore longer range you could substitute a longer screw. It's not your Redfield International, but for a guy on a budget ...

Resp'y,
Bob S.

[FAsmus]

Bob S;

Bob S: The only shooting I have done with the K31 and as-issues sights is the CMP course at 200 yards, or the same...

F: I'm sorry for being so long to respond to the thread. The fact is that I was up in Montana at the 1000 yard Championship where I tied for 1st with my "purpose-built" 1000 yard singleshot rifle. I lost the tie-breaker and wound up with 2nd overall but it was intence and lots of fun.

I don't really intend to shoot the K31 over 1000 yards but we do have a range here in town that has targets placed from 350 yards (the offhand target) on out to 834 yards. This set of sihouettes is used regularly by our club and I do shoot various of my military 30s over the course of fire .. I especially enjoy using my reproduction Camp Perry tool on my M1903 for this work.

Bob S: I can use the Swiss front sight adjuster during a match: I can manipulate it with one hand without disturbing my NPA, and make precise changes. It is not as convenient as..

F: Wow. That sounds challenging although I don't know what "NPA" stands for. In the longer range shooting we do adjusting for changes in condition come pretty much constantly and when comes your turn to shoot, you shoot regardless of wheather your sights are set or not or loose the shot completely.


Bob S; I freely admit that I have not looked at the CBA rules in ages, for the "military rifle" class, you can use modified sights and stocks, but you are restricted to an "issue" barrel? And the shooting is all at 100 yards, or at least not over 200 yards?

F: Well, its been ages since I fired in the CBA Postals and I've never been to a regular match but I do know the rules because I used to score Postal targets for some years.

They do shoot at pretty short ranges; 100 yards max for postals and out to 200 for the Nationals.

There are various classes in Military; As issued, Modified iron and Modified scope ~ too many rules to go into here but you must use the issue barrel & receiver.

Bob S; If that's still the case, I can highly recommend the Swiss Product target sights that are sold by Graf's. They are not cheap, will cost more than the rifle cost you, most likely, but they are a true match grade sight set, and they require no permanent alteration to the rifle: they simply clamp on. If scope sights are allowed, I also recommend the clamp-on scope mount. also available from Graf's.

F: I'll go look into the sites you have recommended. Thanks.

Bob S; For your cast shooting at the longer ranges, I think you're going to need something a little more powerful than what I have developed with cast. I have on my "to do" list to try the Ideal 311334. I have two moulds, and they are poor performers in most "conventional" .30 cal. barrels because the noses cast at .298 from both of my moulds. That should be perfect for any of the Swiss barrels. Based on my US Cal 30 experience, I would try the case full to the bottom of the shoulder (top of the case body) of 4831. You could also try Larry Gibson's load of 26-28 grains 4895 with Dacron.

F: Yes, I've got all those ideas in mind. In particular I'll be trying some Varget since I have discovered its works wondefully well in my rebarreled JAP Type 38 7.62x51.

Bob S: Even if you are successful in finding a load that shoots acceptably well at ranges past 300 yards (and I am certain that you will), you're going to need a rear sight (or telescope) with sufficient precise adjustment in both elevation and windage. The elevation steps on the issue rear sight are way too coarse, and you can't get the magnitude of windage adjustment that you may need by moving the issue sight, even if you do get proficient with the little screw tool.

F: I have looked over your pictures of course and you may be sure that I'll at least be drilling & tapping my rear sight as you have done very soon. The more expensive and capable sights may have to wait a bit.

Bob S: I am currently using a John Wilkes rear sight on one of my K31's, and I am convinced it's the best option out there for anyone who wishes to shoot longer ranges with cast bullets in a K31 and does not mind drilling and tapping the receiver. It has a huge range of adjustment in both elevation and windage.

F: It looks wonderful. Somewhat like the "Diopter" sight that was used by the Swiss themselves? $550 or some such?

Bob S: The small Swiss sight adjusters can be found occasionally on eBay; or you can go to swissrifles.com, and PM or email the gentleman who posts there as "Guisan". His name is Frank Binnendijk and he is in the Netherlands. But his prices are reasonable, and delivery is unusually fast. I guess the Dutch Pony Express is faster than ours!

F: Now that the pressure is over concerning practicing and competing in the 1000 yard match I will be attending back the my bolt guns ~ the Swiss to lead the pack in research& development.

I will keep the thread advised.

Good evening,
Forrest

PS: In that last picture it appears that the operating lever is on the wrong side of the receiver ~ could you explain that?

[garandsrus]

Forrest,

I am nowhere near as knowledgeable on the K-31 as Bob, but I can answer your question abou the operating lever on the "wrong" side of the rifle. There is a fairly simple adapter that allows the lever to be moved to the "wrong" side for all the left handed folks.

Also, Bob drilled and tapped the rear sight, not the front.

I have made a front sight adjusting tool for about $5 following the ideas I found on Milsurpshooter.net and other sites. I used a shaft stop collar and an appropriately sized hex screw. All that was required was to grind the threads off the bottom (away from the head) of the screw for 1/2" or so which allows the screw to push on the sight. It works great from either direction. Here's a link to the thread and a picture of the adjuster I made.



John