Part 5: Two Rivers Arms Yugo M76 Rifle – How to Find the Correct Commercial Ammunition

I’m new to the Yugo M76 rifle and the world of the 8mm Mauser cartridge. When I searched on 8mm Mauser all kinds nomenclature (how it is named) popped up and I had to do some research to understand what to buy. To try and help others I decided to write a blog post to try and clarify what type of ammunition you need to look at for the M76.

IS, JS, IRS & JRS Cartridge Types

When I heard my M76 was almost done being built by Two River Arms, I started shopping for ammo and quickly got confused – I’m good at that. I really didn’t want to deal with old corrosive ammo so my focus was on current commercial offerings and not hunting down old surplus ammo, etc.

First off, you will notice that much of the 8mm Mauser has an “IS” or “JS” designator after the size such as 8×57 IS. The “I” comes from the German word “Infanterie” which means infantry and was mistaken by some to be a “J” so some groups refer to the round using a “JS” designator instead.

When the round was first officially adopted in 1888, it was for 0.318 bore rifles. The “S” dates back to 1903-1905 when “S Patrone” or S ball cartridge was developed for use in S-bore rifles that was larger at 0.323″.

The nomenclature of the rounds can vary because of this and other factors so you are looking for: 8mm Mauser, 8×57 IS, 8×57 JS, 8×57 and so forth. It will likely say IS or JS somewhere especially if it is European but American producers may just say “8mm Mauser”.

Do NOT buy 8×57 IRS or 8×57 JRS. These refer to a rimmed variant that was developed for use in break barrel sporting rifles – double rifles, drilling rifles and so forth. Once in a while you will see it for sale and it will NOT work in a M76. Just remember – if it ends in RS, your day is going to Really Suck 🙂

CIP and SAMMI Specs

The standards body for small arms ammunition in Europe is the Commission internationale permanente pour l’épreuve des armes à feu portatives (“Permanent International Commission for the Proof of Small Arms”. They refer to the 7.92×57 Mauser formally as 8×57 IS.

The US standards body is the Sporting Arms and Ammunition Manufactuers’ Insitute (SAAMI) and they refer to the round both 8mm Mauser and 8x57mm.

I also noticed one interesting detail – the CIP designated rounds are up to 390.00 MPa or 56,565 PSI. Rifles that use the round must be proof tested to 125% of this.

SAAMI is considerably lower at 241.3 MPa or 35,000 PSI and is done is for liability reasons. Among other things, they are concerned that someone may put a modern cartridge in an older narrower throat “I-Series” barrel.

What am I shooting?

I really like Sellier & Bellot from the Czech Republic and they have a number of rounds for the 8mm Mauser listed as 7.92x57JS. The only load I can seem to find from them in the US is the 196 grain Soft Point Cutting Edge (SPCE) cartridge. It functions great and is accurate in my M76. I’m getting about 1.5-2″ at 100 yards with it.

Here’s my S&B 196gr SPCE ammo. It has worked great so far and I am getting about 1.5-2″ groups at 100 yards shooting 5 round groups. I plan on taking my good bench rest the next time I go to the range and see if I can tighten up the groups.

I also have some of the Hornady Vintage Match but haven’t started using it yet. The specs Hornady publishes sure look good and I look forward to trying it.

Hornday Vintage Match 8x57JS. I just bought this and plan on trying this in the near future.

The unique looking top round is the 196 grain S&B Soft Point Cutting Edge (SPCE) round. This is supposed to be designed for medium game including boar, goats and deer. The bottom round is a Hornady Vintage Match cartridge and the bullet is a 196gr Boat Tail Hollow Point (BTHP) .

Where To Learn More

The following websites provide a lot of insight into the 8mm Mauser round for those of you who want to learn more.

Wikipedia has an overview page on 7.92x57mm Mauser
Gun Digest “Cartridges: The Often Overlooked 8mm Mauser
The Concious Hunter “8mm Mauser: 4 Surprising Facts That Make This Rifle Relevant”
American Hunter “Behind the Bullet: 8×57 Mauser”
Ballistics Research has a very detailed article online “8×57 JS Mauser” — this is really a good piece to read if you want details on the history and evolution of 8mm Mauser.

Thank you for reading and I hope this helps you find ammo for your M76.

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