Well I now have a double 7x65R in my possession!

Heym SR20

Well-Known Member
Following on from previous threads Turning a Combination Gun into a Double Rifle

I picked up combination gun from local gunsmith who had fitted the Einstecklauf I had ordered from Germany.

IMG_2637.jpg
The trickiest part in the whole proceedings was persuading my FEO that adding a liner barrel (or Einstecklauf to give it its German name) to my 16 Bore barrel of a combination gun does not a semi automatic rifle make. It took a good four months for my variation to arrive before we could place the order in which time £1 went from c€1.20 down effectively parity by the time you had done the money transfers.

I did consider sending my gun across to Germany to have the barrel fitted :- it would work out cheaper to fly out there with it on my EFP and wait whilst they fitted it and then return.

I placed the order in January. Early march a parcel arrived at my friendly RFD. Three major parts required gunsmithing. The Rim and the muzzle sleeve are deliberately oversized and need maching down to a tight push fit IMG_2638.jpgIMG_2641.jpg


The Muzzle Sleeve fits into the choke and is fixed to the liner barrel about four inches further back. You will see in the muzzle picture above there are four screws - these bear on a taper on the end of the barrel - this allows you to adjust the point of impact to point of aim IMG_2642.jpg

At the breach end there is a tapered brass collar that bears on the forcing cone of the shotgun chamber and this along with the rim keeps the barrel firmly in place. Once fitted it is tight, but requires a few light taps with a wooden rod to remove it.

The trickiest part was fitting a little extractor. The manufacturer drawings showed a simple mortice. Gunsmith was not happy doing that so she instead cut a really nice little dovetail and keeps it all in place with a little screw.IMG_2639.jpg

So its all fitted and ready to be sighted in.

I know that the bottom barrel shoots well, and I expect the top to shoot as well. The tricky bit will be the adjustment to point of aim - that will require a calm day and lots of patience methinks. Realistically If I get two shots into a clay pigeon sized target at 50 to 100 yds then thats good enough for any running pig. I will likely set up a heavy load - 173 gn H-Mantels - copper tipped partitioned bullets for use on Boar, with my 1.25-4 x20 S&B scope as the driven set up, with my current 139gn Hornady load with 6x42 scope as the stalking set up.

It will be interesting to see if given the little extra weight it the bottom barrel still shoots to the same point of aim - hope it does, but not surprised if it does not.

I will report further.
 
Very cool project! It's a bit tedious finding the right loads to get a combination or double rifle to shoot to the sights, but I have found it to be fun, not exasperating. Do post how your current good load with the 139-gr works in the new barrel insert, as well as the 173-gr.

Have you tried using the laser bore sighting tools on your combination gun? I have used the 20-gauge and 7x57R ones on my combination gun, to drift the rear sight. Using one in your already-zeroed rifle barrel, and another in the insert barrel would seem to be a quick way to line up the new insert at 10 to 25 yards, and save some ammo and fiddling.
 
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Looks like a lovely gun. That's a very nice extractor modification and the barrel poi adjustment seems pretty simple - shoots well. Enjoy it!
 
First little snag. On some of my reloads I have not quite knocked the shoulder back far enough. They work fine in the bottom existing barrel, but can't quite close the top. I have about 30 empty cases from my latest batch ready to load - they all fit fine, and so does factory ammo. I do have about 20 rounds though that will go in the bottom.

Not surprising given that it's 40 years difference between the two barrels, plus different makers etc. Also headspaces off the rim. In future I am going to have be careful to really make sure the ram is fully home so I get a full length resize. There is a temptation to stop when it's getting hard and you are a few thou from being full home.

have some new fresh brass on order as well.
 
Thanks for all the info and congratulations on a conversion I've been minded to make since before I bought my first BBF. (I really wanted a Bergstutzen!)

Part of the reason I didn't get anywhere with the idea was the difficulty of finding a gunsmith with the necessary experience/expertise. Do you know of anyone in England, especially in the Midlands, with experience of this sort of work?
 
Thanks for all the info and congratulations on a conversion I've been minded to make since before I bought my first BBF. (I really wanted a Bergstutzen!)

Part of the reason I didn't get anywhere with the idea was the difficulty of finding a gunsmith with the necessary experience/expertise. Do you know of anyone in England, especially in the Midlands, with experience of this sort of work?

Having been involved in the process, the fitting is not complicated, and it came with full instructions - machining down a cylinder to fit the choke, machining the rim to fit the headspace and cutting an extractor slot, and then on larger calibres, drilling and tapping a small hole - (smaller calibre - 222 size tend to have an extractor built into the Insert Barrel - there is room to do it). The challenge is finding a gunsmith who is prepared to do it.
 
Well I got her shooting nicely at 50 yds. Took about 15 rounds but here is the result 2 from bottom barrel and 2 from top.

Photo needs rotating through 90 degrees but the bottom two are at red bull. Top 2 in black. HappyIMG_2649.jpg
 
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Yup same load - 139gn interlock over 51.5gn of IMR 4831. I am happy - it puts all rounds a small group.
 
I was referred to this thread from Accurate Reloading. I have a Krieghoff BBF (Bockbüchsflinte) in caliber 12/7X75R SE vom Hofe which I turned into a Bergstützen with the addition of an Einstecklauf in caliber 6X52R Brettschneider. The cartridge is formed by necking 5.6X52R (.22 Savage High Power) up or 6.5X52R (.25-35 Winchester) down. It propels a 100 grain Nosler bullet at 773 meters per second (ca. 2512 fps) and is legal for roe deer in Germany. In the US, it is legal for white tail deer in most states. Having an instant choice between a long range and a short range cartridge can be advantageous at times.
 
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I was referred to this thread from Accurate Reloading. I have a Krieghoff BBF (Bockbüchsflinte) in caliber 12/7X75R SE vom Hofe which I turned into a Bergstützen with the addition of an Einstecklauf in caliber 6X52R Brettschneider. The cartridge is formed by necking 5.6X52R (.22 Savage High Power) up or 6.5X52R (.25-35 Winchester) down. It propels a 100 grain Nosler bullet at 773 meters per second (ca. 2512 fps) and is legal for roe deer in Germany. In the US, it is legal for white tail deer in most states. Having an instant choice between a long range and a short range cartridge can be advantageous at times.

Tell me more please about the 6x52r - what sort of pressures is it developing?
 
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