Gehmann-Konstanz 5.6 x 61 vom Hofe

[Diz]

Mike,

You got it. I'll get them out as soon as I can and you can just cover it. Nothing has changed with your address?

Thanks, Diz

[mike ford]

Diz,
Thanks, My address is the same.
Mike

[Diz]

Mike, I sent them this AM via USPS. Thanks, Diz

[Diz]

The Sierra Match King 77 grain tipped bullets arrived just before Thanksgiving so I had a chance to load 5 for a test. I bumped them up to .228” diameter same as with the Hornady A-Max. The photo attached shows a loaded cartridge with the Sierra bullet. The cartridge over all length was set at 3.077” and puts the boat tail just against the powder as I did in the earlier test. These bullets are somewhat shorter with the reformed Sierra 77 grain at 1.072” and the A-Max 80 grain is 1.109” Also in the picture are three bullets. On the left is a reformed 80 grain A-Max, in the center is an unreformed 77 grain Sierra and on the right a reformed 77 grain Sierra. You can see the A-Max is longer in the picture.

Sierra for vH.jpg

I have precious few Horneber vH cases but wanted to take advantage of some extra capacity they provide. Just for fun I weighed five Remington cases that I reformed to vH and five Horneber vH cases. The Remingtons averaged 195.7 grains while the Hornebers weighed an average of 195.5 grains. Not much difference at all but internally the Hornebers could hold 58.2 grains of Vihtavuori N-570 compared to the Remington at 56.1 grains when filled to the same place and that is to the top of the shoulder.

My Quick Load predicts about 3465 fps increase due to the lighter bullet and 2.1 grain increase in powder. So I moved out to the range to give them a try.

Below is the five shot target. The problem was that I was a bit sedated from smelling the turkey cooking all morning and lost trigger control on one shot that is marked as “called out” on the target. That opened an otherwise outstanding group to 0.721” center to center. Had it gone in where it belonged the group would have been under 0.400” I guess stuff happens sometimes.

vom Hofe Target - 77 grain Sierra MKT.jpg

So now for the numbers. The chrono printout is below and it shows a high of 3488 fps and a low of 3384 fps for a difference of 104 fps. This is the result of that low reading as the others were all quite close and would have reduced it considerably. The average was 3457 fps which is very close to predicted. The SD was a bit bigger than the last time at 41 fps but the accuracy was outstanding. I am more than happy with these results and it’s time to put it away for awhile.

Chrono 56x61vHSE with Sierra 77 grain MKT.jpg

I suppose I should have put this together as an article for Waidmannsheil! But I had a lot of fun and I am very happy with the results. Please be extremely careful if you want to try any of these loads as your results may vary.

Happy Thanksgiving, Diz

[sharps4590]

Geezo-Pete criminy! You think that cartridge is a little over-bore....lol!! That's a small bore beast! Very interesting, very interesting. Good shootin' too!!

[mike ford]

Diz, I agree that is great shooting, especially from an "old fart". You are going to make a lie out of my excuse of being too old.
Mike

[Diz]

Sharps & Mike, that's high praise indeed coming from you two. "Old Fart" certainly fits but I always say it isn't the age it's the mileage! I've got a lot of miles. Try as I might I couldn't break into the 3500 fps zone but this isn't a compressed load and the primers are just starting to flatten, so there is a little more yet to get. H-870 was a bit faster but burned another four grains and couldn't keep the grouping without cleaning. This last test didn't have a hint of anything left in the tube. I am not interested in pushing it to the limit and now just want to reserve what I have so I'm going to let it rest. It certainly was an interesting exercise!

I did get the 400 grain SWC mold for a .501" diameter bullet to use in the 12.7 x 44R and cast a few. It's a good looking bullet and I will try them tomorrow if I can with some Lil Gun. I'll report that on the other thread.

Thanks again and best wishes, Diz

[sharps4590]

You better get after it today if the rain we're getting now continues on to you.

[mike ford]

Diz,
I too, think it's time to stop working on the 5.6. With groups like those above, I don't see room for improvement. It's been said that " you aren't having fun until you blow something up". I don't advise this policy, especially for those of us already having trouble with old eyes. In addition to the wonderful groups, I suspect your velocities are as high or higher than actually achieved(as opposed to reported) with sporting length barrels and factory ammunition. I think a thread on the 12.7x44R would be interesting and applicable to old German cartridges. I haven't used Lil Gun in similar cartridges and am interested in what you find.
Mike

[Diz]

Mike,

I just finished cleaning the rifle for it to go back in the box and just have a couple comments to make. I think there may be a little left in it as I mentioned but it would take compressing the powder to achieve it. I am more than happy with the groups I got and so I think I can put it away thinking I didn't leave much on the table.

I also wanted to comment on the Sierra bullet. This is not a very scientific comparison but during clean up I didn't see nearly the amount of green from jacket material coming out of the bore as I did with the Hornady A-Max. Does it mean anything? Possibly that Sierra has a better jacket composition for the high speeds and maybe over a long string of shooting you might see something due to jacket fouling from the Hornady but my guess with this cartridge is that powder fouling would show as a problem long before. I know it did with Hodgdon H-870.

I am sure it has been discussed before on this site but the 5.6 x 57 had been mentioned somewhere in this thread and I really caught my interest. For the sake of conversation and my learning more about it does anyone have real experience with this cartridge and rifles that go with it? Possibly hunting experience as well?

I have been working on the 12.7 x 44R and fooling with some tools to bump up a 358" rifle bullet to use in my 9.3 x 72R and would be happy to report on those.

Everyone please feel free to comment on this thread, good, bad or otherwise. It has been great fun.

Thanks, Diz

[sharps4590]

I'm always ready to read about load development, cartridge conversion and now jacketed bullet making for any cartridge/rifle combination.

As I mentioned Diz, I've never really been a small bore/high velocity guy but, your work and reports on the vH has been really interesting. We all come to a stopping point when working with a rifle/cartridge and it seems to me you stopped when you had precious little left that could sensibly be accomplished concerning both accuracy and velocity. Good work, fine report.

[mike ford]

Diz,
It might have been me that mentioned the 5.6x57, I have been working on one for 25 years or more. I hadn't planned to do much loading for it, because I brought a "pile" of ammo back from Germany(can you think of a better reason to build a rifle? I thought finding a set of 9x57 dies was good enough many years ago). It's not nearly finished, but I could likely chronograph some factory ammo, if it would help your project- but in the spring. I thought if I loaded for it, I would use the 60gr partition bullet. I used a 5.6x57 Heym barrel blank and the standard twist is only a little tighter than 1in10; 1in250mm, as I recall. This is right on the edge for the 74grain bullet they use. I had a couple friends that used that caliber and one of them had trouble , a couple times. The first time, Walter recrowned it and that worked for awhile. I don't know if they found the second problem( it may have been fouling, not all hunters were riflemen). The other was a Forester and he liked his, even using it on female and young Red Deer and pigs. He wasn't really allowed to do that, but it put them on the ground. He was one of the hunters that was a rifleman and "gun nut". I know you like long bullets, so you might want to use a faster twist. It might be worth another thread.
Mike

[Diz]

Sharps,

Thanks for the kind words and i know you aren't a fan of the flaming hot small bores but I am working on the 12.7 and should have something soon.

Mike,

I believe it was you that mentioned it and I started looking around a bit at the specifications. It is a pretty hot number as RWS loads it. I believe I read that it goes 3380 fps with a 74 grain cone point bullet. There is no mention of barrel length in the info I found but I have to think it is reasonable. Plus that bullet is meant for medium sized game so it must be substantial as far as construction goes. People would debate this but I always thought most of the European bullets were better constructed than those here. I really don't see a big issue with the thick neck for reloading but I don't know what brass you could make it from and come out with something that would work. I am going to look for a rifle in that caliber just to see what I can get into. If you want to open up a thread I would be very interested in reading about it.

Thanks, Diz

[mike ford]

Diz,
If my memory serves, the barrel length is 60cm or about 23 1/2". The American bullets in this diameter, until pretty recent developments, were intended for varmints , while Germans didn't hunt "varmints" per se. If you make cases from 30-06 (especially military), the neck will likely be thick enough. It would be a tough forming job though. Maybe you could find some factory cases and avoid this. As slow as I am, it is not likely I will open a thread.
Mike

[Diz]

Mike

You are likely correct about using the 06 as a case. They get thicker as you move back and that may be well enough. I'll have to see what I can find and afford for a project before I go off trying to make ammo. Perhaps there is someone else that has experience with the 5.6x57 cartridge that would like to share.

Thanks, Diz