The 7.5x55 Swiss

[rvpilot76]

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

Good eye!

[FAsmus]

Gentelmen;

I've been active with the K31 today and have an update.

I looked over my rifle over the last week or two, comparing it to the standards as provided by Bob's Swiss information.

Now, I'm only your average semi-amature shooter but, really, it looked quite close to the perimeters specified there. I didn't mess with the issue stock at all but simply re-assembeled it carefully and loaded up some more ammunition to see what I could see.

I moved the front sight over to print zero on my 100 yard paper and fired the standard loads that work in so many similar cartridges. Things like 20 - 22 grains 4759 and such under a bullet that seemed pretty close to fitting the tight throat without extending below the shoulder of the case .. I picked the SAECO 316.

I'm used to the fairly easy-to-use tang peep and aperture front sights as used on big singleshots so going back the as-issued military took a little recurrent training.

The rifle performed very well once I got back into currency, shooting one of my combinations into 5 x 1.580 and another into 7 x 1.630 .. The 7 shot group was with 29 grains of "Varget" so it's getting out there fairly fast ~ now where in the world can I find some more of that stuff?!

Its early days yet but I'm confident that this rifle will go the distance and be very interesting every step of the way.

Good afternoon,
Forrest

[FAsmus]

45 2.1;

I hope you may still be following this thread because I'm interested in hearing more about how your RCBS 30-165-SIL works in your K31.

So far I've been shooting bullets cast in borrowed molds with fair success but the time is approaching for me to buy a mold of my own. I like the appearance of the RCBS silhouette design, being short in the body and long in the nose.

How deeply (for example) does the bullet seat into the case as permitted by the short throat? As loaded for your rifle does the bullet base extend below the case shoulder?

What size is your particular bullet as-cast on the body and the nose? (I know this is unique to each mold but any data is good)

Thanks for your help, good evening,
Forrest

[FAsmus]

Gentlemen;

No luck on getting 45 2.1 to come back I guess.

Lately I've taken the K31 up for addional testing with the good Varget load. Unfortunately there was no consistency shown this time; lots of open groups and flyers.

It'll have to be overhauled according to specifications recorded in this thread I guess but perhaps I'll wait a little ~ until the weather gets too crummy for much shooting .. for now I have some other rifles that are already doing just fine.

Good afternoon,
Forrest

[FAsmus]

Gentlemen;

An an update on the K31 here.

The deal is that I was wrong about the orignal bedding being semi-resaonable - it wasn't. No combination gave me anything like good groups. But! There was always the indication that the rifle "wanted" to shoot as it would occassionaly produce nice little clusters - but no repeats.

I looked it over with a mind to get out the epoxy and go to the standard bedding procedure as is done with the typical Mauser action. But, I hesitated; "This is no Mauser" I thought and reviewed the text of the bedding procdure as posted in this thread.

Instead of gooping up the action with the epoxy, forevermore destroying the possibility of shooting "As Issued" I decided to try shimming the action in stages to see what I could see.

This worked. I added various thicknesses of shim in the recoil transfer area of the stock and under the tang until I wound up with 0.036 under the tang and 0.009 behind the recoil surface of the trigger-group portion of the receiver where recoil is transfered to the wood.

Instantly the groups became lots smaller. I could see occaisional three or four shot groups of a 5 shot run as small as 0.750. To me this ment that the rifle was doing first-rate - it was me not being able to see the issue sights dead-nuts that was opening the groups.

It is early days yet, and many more rounds to be fired but I believe that this K31 is on its way to the record books - perhaps in the "As Issued" CBA matches yet to come.

Good evening,
Forrest

[coyotebait]

FAsmus

I've been following this thread with intrest as I too have a few K31 rifles and have worked on some cast loads for one. I will offer up a little info about the RCBS 165-SIL. Cast from WW the nose ride is .299 and must be seated so the GC is below the neck in order to chamber in my rifle. OAL 2.775 YMMV

coyotebait

[FAsmus]

Coyotebait;

Thanks for the post.

I am particularly interested your reported use of the RCBS 30-165-SIL design since I am seriously considering getting a set blocks for it myself. The price seems a little high for outright experimentaton though so feed-back from members is greatly appricated.

My current RCBS 30-180-SP is a very good design but unless I run them through my Wosika Coaxisizer die they too require a seating depth such that the GC is below the neck of the case.

Now, I've always liked the Coax die. It does what its supposed to do and I have always noted an improvement in accuracy when I used it. However, running all my bullets through the procedure is a time-consuming pain so I really do try to find an as-cast design that will not need the extra work to make it shoot ~ your word on the Silhouette design has helped me make the choice to stick with the SP design - at least for awhile yet.

Could you tell me, please, what portion of the Silhouette bullet engages the throat of your rifle first? Is it the nose at 0.299? Or the body at (non-specified) diameter?

Good morning,
Forrest

[FAsmus]

Bob S;

A question has arisen about your Precision Elevation Adjuster, Mark One, Mod Zero:

I took my sight apart and got a good pin-punch into the center of it with my old machinest's tool. Then I tried making the locater mark big enough to center-up a drill with a regular center punch .. the freshly sharpened center punch simply mushed off the sight material without changing the initial marker at all and my regular high-speed steel drill didn't even remove the bluing from the sight, let alone cut a thing.

Obviously the sight is pretty hard and I see the discoloration on your sight from drawing it back. I'd be interested to hear about the full procedure you used to drill & tap your elevation screw hole!

I mean, sure, I can draw back my sight too but I'd just like to hear about what you did first ..

Good morning,
Forrest

[Bob S]

Forrest:

I just annealed the leaf with a propane torch. Remove the slide first so the heat does not draw the temper of the spring that is inside of it. I clamped the leaf in a bench vise at the very front end on the pivot bosses so there is very little contact with the vise that would draw off the heat. Heat the spot you wish to drill to a dull red, and then let it cool in air.

Resp'y,
Bob S.

[coyotebait]

FAsmus;

With regards to my RCBS 30-165-SIL in my K31, the .299 dia. bore ride engages the rifling just behind the ogive. When seated long enough to keep the GC in the neck it takes a sharp rap on the bolt handle to close and risks leaving a bullet in the chamber when removing a loaded round so I seat deeper to avoid that problem. If you PM me your contact info I will mail you a handfull of bullets as cast to try in your rifle.

regards
coyotebait

[FAsmus]

Bob S & Coyotebait;

Thanks for your posts.

Bob - I'll follow the procedure. I only wish I might find an extra sight leaf for this purpose. Ah well, civil shooting will virtually never wear out even a softened sight I'm sure.

Coyote; Check your PM ~ We're in business! Thanks for the offer.

Good evening,
Forrest

[Bob S]

Forrest:

If you would like to keep your rear sight leaf pristine and unmodified, you can purchase a spare from Graf's, and modify that one:

http://www.grafs.com/shooting/3964

(Scroll down to the bottom of the page)

Resp'y,
Bob S.

[FAsmus]

Gentlemen;

The K31 is shooting well with the coaxisized RCBS 30-180-SO and 28 grains Varget; Even with only the issue sights and my semi-marginal eyes I can count on 5x1.500 groups at 100 yards ~ always provided I do my part.

My only problem is that running any great number of bullets through the coax tool gets to be a pain and my RCBS SP is just too long and too big for the rifle unless I cold-form them prior to seating them into cases.

However! By now, member Coyotebait has shared a few RCBS 30-165-SIL bullets with me and these seem to be, if not an actual "magic bullet" for this particular K31, they appear to be pretty darn close to it in size and configuration and no-need to coaxisize them either.

Good afternoon,
Forrest

[FAsmus]

BobS;

Since last addition to the thread I have received a sight piece from GRAF and modified it.

I looked it over and thought about options. Your screw elevation idea is good of course, but keep in mind that my main consideration for fiddling with the sights at all has always been to find a way to come up with a modification to adjust for windage. This, without going for the big-bucks sights from Europe.

Then I remembered I had an unused Lyman 57 receiver sight in my bag of parts. I got it out, placed it next to the K31's sight and soon figured out the method needed to put the two of them together.

I cut off the sight piece after drawing out the temper and filed it square. Then I cut off the windage portion of the Lyman sight and fitted the pieces together. The addition of an 8/32 threaded hole, which is where you left off, didn't seem all that handy to me .. the hole was pretty big and didn't allow for high sight settings without repeated changing of set screws. Instead I drilled and tapped two 4/40 holes on either side of center so that regardless of how long the screws might be they would never be in front of center. I made two holes so that in case I needed the full travel for windage I would be able to use one side or the other and still remain clear of the peep's line of sight. Things looked good so I welded the parts together and assembled the whole works on the rifle.

Today I am loading for the first trial of the modified sight .. I'll keep you advised.

Good morning,
Forrest

[Bob S]

Forrest,

One thing that I considered, but never actually did was to adapt the sight leaf from a SMLE to the K31 base. I have a few of the very early SMLE leafs that have fine elevation adjustment, and windage adjustment as well. (I think the Brits discontinued the windage adjustement about the same time they removed the magazine cut-off ... 1916?) You'd still have an open sighting notch, but in that position an aperture doesn't do you much good, anyway.

I did the same thing with the offset 4-40 hole on a Swiss Vetterli, only one hole, and a very, very long screw in it. The 10.4 mm Swiss bullet has the trajectory of an 81mm mortar, and needs lots and lots of elevation for 300 yards!

Would appreciate pictures of your sight set-up when you get a chance. I'm sure there are others here who would also like to see it.

Resp'y,
Bob S.

[FAsmus]

Gentlemen;

Today was the first time for the K31 to go up on our hill-top range to try out the sight modifcations outlined in the thread.

My load was 29 grans Varget and the RCBS 30-180-SP as coaxisized with the Wosika tool .. I have not been able to cast up a "shootable" number of Coyotebait's 30-165-SIL bullets yet, but that is another story.

The wind was light from the east, sometimes going pretty much flat; ideal for testing a 30 caliber cast bullet load at long range without adding too many additional challenges. I set up my cross-sticks, scope and ground cloth, set out the ammunition, screw driver and sight-setting book beside me and got with it .. fortunately about then another shooter showed up, interested in testing his 7.62x51 on the M70 action, the main difference was that he had a full set of Redfield "Olympic" sights ~ "Fortunately" I say because the little 30 caliber pills really are hard to self-spot at anything over about 400 yards and I planned on shooting on out to 834 yards; with him coming along we were both enabled to spot for one another..

We worked out to the 470 yard Rectangle, getting good hits, before my peep sight picture started looking decidedly out-of-round. This problem was unavoidable since the sight, as the screw increased its elevation became further and further off the line of sight. I had forseen this so I stoped shooting for a minute, added on one of my 0.400" sight extentions to the peep, put it back together, lowered the elevation screw and returned to shooting.

Once this was done no further problems with out-of-round sight picture were encountered right on out to the 834 yard distance.

The sight radius is 23 inches and I found that the very slightest movement of either elevation or windage REALLY changed point of impact more than I'm used to with the typical 33 to 34 inch radius rifles I usually shoot but once understood it was doable.

The windage adjustment was easy, since as you can see in the pictures I graduated things so as to keep track. Elevation was tougher since the issue method for controlling elevation was rendered completely inoperative with the modifcation I'd done. All I could think of was to measure the elevation directly with a machinest's scale and record these numbeers in the sight-setting book .. A little slow maybe but I got the numbers and they repeat.

Things were going quite well right on out to the 670 yard Circle, then the wind came up a bit. At first I didn't catch on but then I realized that I couldn't see the front sight clearly anymore because the elevation screw was blocking the way. Good! This was why I made two holes for the darn thing and it needed to be tested too; I moved the screw from one side to the other of the sight, measured the elevation to get back on target and presto! It worked just as planned.

On out to the 834 yard Big Square I had to hunt around for bit with my friend's help - the misses being pretty small way out there and I having no idea about where to set the sight on this, the first time the rifle had been on the long range line, it took five shots to "find" the steel. ~ then, once on it it was as usual a challenge to stay on it while conditions changed .. but fun.

Finally I ran out of the 30-180-SPs and turned to the 5 rounds I had loaded with the 30-165-SIL; I had cast only a few and these just had to come along so see how they did at long range. The first round was about 5 feet high from the previously set zero for the heavier bullets. I adjusted the elevation and ran the last four straight hits. My! I sure like the SIL design in this rifle.

With this shooting I have reached the set goal of making the K31 perform over the distance. Now that the rifle works, the rest is up to me and I look forward to the slick striaght-pull and fine acccuracy in the times to come.

Good evening,
Forrest

[madsenshooter]

What's the ID of the K31 rear sight mount, I mean where it fits around the barrel. I have this rear sight from a Danish Madsen that I got off ebay, it already has windage adjustment, might just work.

[45 2.1]

45 2.1;

I hope you may still be following this thread because I'm interested in hearing more about how your RCBS 30-165-SIL works in your K31. I guess its been a while since I viewed this thread.

So far I've been shooting bullets cast in borrowed molds with fair success but the time is approaching for me to buy a mold of my own. I like the appearance of the RCBS silhouette design, being short in the body and long in the nose. The RCBS mold comes in several different "lengths" due to different cherrys being used with a little dimensional difference between them. The RCBS boolit actually fits the 1911 K11 better than the K31 and is more accurate in them. The K31 has a long chamber neck and an abrupt throat. Depending on which GB version you have, they fit the K31 better or worse than the original. Best to have some of the nose engrave for better accuracy.

How deeply (for example) does the bullet seat into the case as permitted by the short throat? The base of the boolit and the case neck are usually the same in my loads. As loaded for your rifle does the bullet base extend below the case shoulder? No, not on any of them. The various versions of the Sil. boolit sometimes are too big and try to engrave the nose too much in some of the K31s i've tried, not all though.

What size is your particular bullet as-cast on the body and the nose? They vary from 0.3095" on the RCBS version to 0.3115" on the GB versions. (I know this is unique to each mold but any data is good)

Thanks for your help, good evening,
Forrest

Try sizing to 0.310" or 0.311" depending on your rifle and useing either 11.3 gr. or a top level charge of Unique or slightly less with a boolit no harder than air cooled WW.

[Bob S]

Try sizing to 0.310" or 0.311" depending on your rifle and useing either 11.3 gr. or a top level charge of Unique or slightly less with a boolit no harder than air cooled WW.

Sizing larger than .309 for a K31 is generally an exercise in futility. Groove diameters usually run less than .308, and they have no throat. Seriously, no throat.

Resp'y,
Bob S.

[45 2.1]

Sizing larger than .309 for a K31 is generally an exercise in futility. Groove diameters usually run less than .308, and they have no throat. Seriously, no throat. I believe you should reread what I posted previously about a long neck and abrupt throat in the K31s. I have done throat slugs on quite a few. The Swiss rifles are quite well made and uniform. Brass, on the other hand, can vary considerably considering at least 7 or more potential sources. So larger sizing diameters can be tolerated and produce excellent accuracy.

Resp'y,
Bob S.

I've played with most all the varieties (in unmodified form) of the Swiss rifles since 1978 and know what they'll do with various boolits and loadings. Some folks do get into it farther than you have.