8x56R has a very loose neck tolerance. Blanks are low powered and some people form 8x56R from 7.62x54R ammo. I would think 7.62x54R blanks would work, or at most you could just run them through a sizing die.
If you are using an 8x56R chambered rifle, one can get away with Czech 7,62x54R Long blanks...they are "undersize" all over, and will seat well and fire(they may split in the neck shoulder are, may not.)
If you are using an 8x50R chamber, then Resizing is essential, to shift the shoulder and mouth back, but the length is OK.
As the rim is the operative dimension,,,it is OK for all.
For movies in close up, we mak "proper" brass Blanks (long) from 9,4x74R cases (expensive, but correct profile and colour) and for general Use, we use iether Resized berdan 8x56R cases, or even Pulled Milsurp cases. We even make the 8x50R Blanks from these (the 56R cases); MGs get a new barrel to take 7,62x54R Blanks as is. And since the MGs are belt fed, (pull out type,) even Ball cases can be simply crimped over to make functioning Blanks
(no "profile" required.
AV Ballistics Film Ordnance Services.
Here's my experience--the shorter Czech 7.62x54R blanks are a single-shot proposition, they won't feed from the magazine at all. I used some full-length 7.62x54R blanks with mixed success. They will feed, but not reliably, with the first round of a clip being the most problematic. I also notice a fair number of split necks, but I didn't have any extraction or ejection problems. Next time out, I'm going to try the .303-based blanks.
Short 7.62x54 will feed just fine, if an bridge like adapter is inserted into the magazine chamber.
I'm having great difficulties with Romanian blanks (grey ones) with the red tip, designated for MG. When fired, they extract with great difficulties (i must use a leg to open the bolt ) or they do not extract at all. Do you gentlemen think is an powder issue. Are they too strong? They are fire formed allright but they split.
Is maybe an option to make blanks from original 8x56R brass an then crimp them? Is it expensive to do that?
I think that most 7.62x54R blanks are loaded "hotter" than they need to be, leading to the split necks and extraction problems. I believe the Romanian blanks are steel cased--I would not use them in an M95. Privi Partisan in Serbia makes new 8x56R brass, but I don't know how difficult/expensive it would be to crimp your own blanks.
Yes, Romanian blanks are hotter than Czech (copper plated). I've noticed. Prvi Partizan Užice (PPU) has brass, but its pretty expencive (i believe cca. 80Euro for 100), the powder would be cca. 50E, primers cca. 50E ( per 1000), work not taken into account) i believe around 1Euro per round. What type of ammo do you use on your reenactments?
I've been using Atlantic Wall full-length 8x56R blanks, which they load using PPU 7.62x54R brass; cost is about US$0.55/round (plus shipping). Currently, they are having trouble getting brass, due to the current high demand for live 7.62x54R rounds. Here is their website: http://www.atlanticwallblanks.com/