Successfully converted 9.3X74R to .30R Blaser!

As some of you know. A few months ago I landed a sweet Chapuis Super Orion Express O/U double rifle in .30R Blaser. Luckily it came with 3 boxes of RWS ammo but I wanted to get more for it. After extensive searching it became apparent that not only ammo, but brass as well, is unobtainable in the U.S. After doing more searching I found that it was supposedly possible to convert 9.3X74R brass to .30R. I have never messed with wildcatting or converting brass so I was hesitant, but after receiving an excellent offer for brass to attempt the conversion, I decided to give it a go. It required a fair number of steps but were accomplished with basic equipment. I have no hiccups along the way and just fired my first rounds to fire form the brass with no issues. Needless to say I’m pretty pleased with the results and now have an unlimited supply of brass for this rifle. I’ll be saving the RWS for correct headstamp in case of travel. If anyone is interested, I’ll be glad to lay out the steps I took to make it work.

Step by step description with pictures?
Always nice to see what lengths others go to to make brass, make me feel better about some of the weird stuff I make at times
Gumpy

1. Acquire .30R Blaser dies, Neck sizer mandrel and body ( I used Sinclair International from Brownells) and 8mm Rem Mag FL sizer die- this is to bring the neck size down in two steps rather than one which helps prevent several possible issues with the brass. 8mm RM is a larger diameter body than 9.3x74R so it only reduces the neck and does touch the rest of the case.
2. Anneal the brass- neck and shoulder area only, very important due to working the brass several times during the process ( I just use an annealing mandrel and torch) be careful not to overheat the brass and ruin it- it should not glow cherry red, only a dull red, this has to be done in a dark room to see it
3. Remove sizer plug/ button from both sizer dies, lube brass well and run through the 8mm die first, then the .30R. Have dies backed off slightly so you do not cam over on the press.
4. 9.3X74R brass has a slightly thicker rim than .30R so you will need to thin it. I just used my table belt grinder. Use gentle pressure and only briefly touch it to the belt a couple times until the headstamp can only faintly be seen.
5. Cut the necks. After sizing you will have extremely long necks. You will need something to cut the brass off slightly longer than standard case length. I used a dremel tool, set in a drill press stand with the cutoff wheel set to the correct height, then gently fed it in while holding the base flat to the table, worked fine.
6. Use trim tool to get a square cut to final length
7. Chamfer/ deburr case mouth
8. Test fit to rifle- may need to thin the rim a bit more or run through the .30R sizer set a bit deeper. The idea is to have the brass be as long as possible but still get the action to close so that you minimize stretch during fire forming.
9. Once all brass fits, run through neck sizer mandrel to set neck tension and ensure they are square to the case body.
10. Seat a bullet in one of the cases and measure the diameter of the neck brass. If you are lucky, it will be under .344” and you are good to go. If it is thicker than that, you will likely need to turn the necks to get a loaded round to chamber. I did not have this issue thankfully.
11. Load cheap bullets at slightly above starting charge for .30-06 and fire form. Check cases for separation, cracks etc. If all is well, you are good to go!

Sounds like a ton of work!

I wonder is Starline could be convinved to make a batch of brass?

matt85 said:

Sounds like a ton of work!

I wonder is Starline could be convinved to make a batch of brass?

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No idea, but it wasn’t actually that bad. Not running into any problems and just being happy to have brass to load, I think it mitigated any grief over the process, lol

Congratulations. It sure is rewarding when you see an effort like that through to successful completion. You may no longer view any rifle in any caliber “obsolete”.

Albert GRANT said:

4. 9.3X74R brass has a slightly thicker rim than .30R so you will need to thin it. I just used my table belt grinder. Use gentle pressure and only briefly touch it to the belt a couple times until the headstamp can only faintly be seen.

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This will work acceptably if you need just a couple thou removed, but what it really does is reduce the depth of the primer pocket as it thins the rim.
The correct method is to thin the rim from the other side (front?). You can do this by putting the brass in a drill press chuck or lathe and use a safe edge file to thin the rim.

Huvius said:

This will work acceptably if you need just a couple thou removed, but what it really does is reduce the depth of the primer pocket as it thins the rim.
The correct method is to thin the rim from the other side (front?). You can do this by putting the brass in a drill press chuck or lathe and use a safe edge file to thin the rim.

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If it needed any more than light scuffing I would have done something like that, but with the minimal amount taken, primers seated fine, still slightly below the surface.