Head size difference

[andym79]

Hi guys I am wanting to do a 35-90.

The idea going through my head at the moment is to use 45-90 brass and a 350 rem mag reamer run in .375" short. Using dies cut short too.

My only concern is case head diameter, being .513 for a 350 and .506 for a 45-90!

Is a .007" difference too much or okay?

I am hoping to end up with a rimmed 35-90 using cast bullets and either bp or trailboss so pressure will be low, but will I likely get a bulge at the head or worse a split?

[Jedman]

Andy, Consider using the 358 Norma Magnum shortened to just above the belt.

Jedman

[EDG]

The chambers of .303 Lee Enfields run .007 to .010 larger than most US made brass. You get large steps at the pressure ring formed at the junction of the case walls and the solid head. The cases also separate within 2 to 5 reloads. The same brass can be formed to the 6.5X53Rs Dutch Mannlicher with only .002 to .003 clearance. In the Dutch chambers the same brass lasts many reloadings with no case head separations.

You might actually check the interior dimension of a .350 magnum die and the actual dim of a .45-90 case. Just because the specs say something does not mean the actual tolerance do not give you something else.

You might consider getting away from the use of the rimmed 45-90 brass if you can. It is expensive and only has one source. Single sources of anything are bad. If that item is discontinued you have no source at all. In addition I do not care for the Starline brass since they are too lazy to anneal it properly before selling it. It is very hard and cracks easily when formed. I found that out forming it to the 8X56R Danish cartridge.

You might consider using the .356 Win since dies and reamers are easy to find. If you want a longer case you can use the .444 Marlin.

More difficult to find are .35 Win dies and reamers and this .35 requires .405 Win brass unless you use a short version with the .303 Brit or .30-40 Krag case.

I have a box of .375 H&H brass near my keyboard.
Resized twice fired cases measure .510 immediately ahead of the belt. At .500 to .562 ahead of the belt the cases measure .500. Both dimensions are .002 larger with cases fired with mild loads. Were it me I would use a chambered.375 H&H barrel shortened enough to fit .45-70 brass. The result would be something like a .38-70. You can use a take off barrel and cut down standard dies. You can also use standard .45-70 brass which gives you a lot of brands and sources of brass. Most of them are annealed and will be easier to form than Starline. If you do not like the shorter .45-70 version you can still use the .45-90 version.