.30-.375HH M&R

[CZ]

Some years back about 20 I sent an action to be made to Ray Romain in PA, he built me a very nice rifle which I sold and got it back now. It is well conserved a Máuser-interarms action and a nice Hart barrel chambered in .30-.375HH M&R

Have a question on this one, anyone know about the chambering? about Romains build ups? and any suggestion on loads..... maybe a good start would be a .300 Weatherby loading? Any info will be appreciated.

 

[FOTIS]

If the tapering is close to the 375 Holland you might be looking closer to the 300 H&H as a start.

 

[baltz526]

is it .440" at shoulder or .490" If .440 it is close to 300 win mag capacity. If .490" it is close to 300 Weatherby. But if it doesn't have weatherby free bore you have to start below starting loads by 4-5gr. If you have a case We could get a very good Idea Of what capacity it is close to, if you fill a fired case up to base of neck with a magnum rifle powder.

 

[Vince]

I'm interested in hearing about this.
Please keep us informed of your progress.

Vince

Sent from my SGH-M919 using Tapatalk

 

[FOTIS]

pictures of a case?

 

[CZ]

Will fireform some cases this next week, will start low with min charge of imr4350 over a 150gr bullet, a la 300HH capacity, then will measure H2O capacity.

 

[SJB358]

Sounds pretty neat. Love to see some pictures of it.

 

[HomerOz]

G'Day Fella's,

CZ, if it isn't as suggested above, it may be a Wildcat version of the .300 Weatherby?
As suggested above, an image of some loaded or fired cases, would help heaps!

CZ, if you don't have any ammo or empty cases to suit this rifle, that makes things a bit hard to ID this chambering!
If you can chamber an EMPTY .300 H&H case but not an EMPTY .300 Weatherby, that would answer some questions!
If the EMPTY .300 Weatherby case does chamber without problems, well that sort of addresses this question just a little bit more..............???
If neither of these will fully chamber, you may need to get a competent Gunsmith to do a Chamber Cast (with Cerosafe), on this rifle!

Hope that helps

Doh!
Homer

 

[SJB358]

If you can chamber a 300 H&H, maybe load it up with about 15 grains of Bullseyes over some Cream of Wheat and a pistol primer. Should give you a decent idea of what it looks like?

 

[CZ]

seems I have a la .300Jarrett.- 95gr H2o wáter capacity to sholuders

 

[CZ]

1st.- .300 Wby
2nd.-.300 Jarrett
3.- .30x375 M&R
4.- .300 RUM

 

[IdahoCTD]

It almost looks like the shoulder is a bit further forward and a bit sharper than a 30-358STA (aka 300 Jarrett) but I'm sure the performance is almost identical. I've done a 30-8mm, 308 Baer, and 30-358STA and they are all within about 50fps of one another or about 100-150fps short of a .300 RUM.

 

[CZ]

Loaded some 220 Sierra Matchkings Cal.30 with 2 more grains over max over the Wby loading and got 2886fps, will add from 3 to 5 gr more to the load, and will test fire with some groups. Think will be a lil under my .300 RUM.