1891 Argentine re-barrel caliber?

[ronniet]

I would like to ask is if it is possible for the 1891 Action to be chambered for the 9.5x56 Mannlicher S.? Alias .375 NE.
The .375 NE cartridge is the very close to same length and rim diameter of the original 7.65x53 load and the pressure of the .375 load is listed lower @ 44,000psi where the 7.65x53 is recorded at 55,000+
Am I reading these figures right or am I overlooking something important here.
A larger case and lead but lower in pressure?
I know pressures range differently in different cases/bullets like a 38-55 and 45-70 are large loads but are smaller in pressure than other cartridges in their categories.
I am thinking of Cast bullets , haven't decided on a length or barrel profile/twist as yet, but am thinking of about a 260gr. GC bullet loaded on reformed 8mm Mauser brass.
Chime in if you have any advise or experience on this .
Disclaimer, I didn't not tear up an 1891 Rifle , I know purists do not like this, I "rescued" the action and bolt from a trade and added the other parts from "surplus retailers".
Thanks
Ron

[SvenLindquist]

Have you talked to JES about a rebore ?

[ronniet]

Have you talked to JES about a rebore ?

I don't know "Jes" what does he do? I don't have a barrel as yet or a stock I am wondering about pressures at the moment.
To see if its doable?
Ron

[John Taylor]

I have one in the shop now that is going to be made into a 250 Savage.

[EDG]

The only problem with the 9.5x56 is the dies may cost more than your completed rifle is worth.

[ronniet]

The only problem with the 9.5x56 is the dies may cost more than your completed rifle is worth.
I have a 250-3000 savage in one also, thank you, Dies are not a problem, I am unfamiliar with the cartridge and want to make sure the action is strong enough , as I look at it on paper , I see nothing unusual that it could be done as the Mannlicher S rifles were made in some of the 1888 types and they used this cartridge in those.

Just don't see this cartridge everyday even though it is old as the 1891 is.

Ron

[Texas by God]

Isn't the 9.5x 56mm too long for the 1891 magazine? Members here have posted their .35 Remington 91 conversions and that would be neat.

[CA Dude]

I am going to build a rifle in this cartridge. You might have a problem getting it to feed from the mag since the shoulder is much larger than the 7.62 x 54 . That would be easy to test by put a 257 Rob ACK Imp case in the mag and see how it feeds. I bought a barrel blank from SACRO for $60.00 plus shipping. My Smith bore scoped it and said it should work fine. When I push cleaning patches through it; it went smooth. I really think it is a Savage barrel. As for reloading dies I just ordered a set from CH cost me about $116.00 with shipping. I hope to get them in a couple of days. My rifle is stamped with "Made In England" so I'm going to stamp the caliber as ".375 Rimless Nitro Express 2 1/4". As for pressure the "strongest" load I have found for it is running about 46,000 psi and that is within the range I have read for the Model 91.

[Moleman-]

Measuring a Lowe 1891 magazine the inside length is around 3.090" so figure 3.050" will be the longest COL that will feed smoothly. No idea what the COL is on a 375NE. Pressure is ok, looks like bolt thrust is similar. If it'll feed and makes you happy why not. I'd get some rounds or make up some dummy rounds to see if they'll fit and feed in the single stack magazine.

Pssst... make the barrel octagon!

[SvenLindquist]

I don't know "Jes" what does he do? I don't have a barrel as yet or a stock I am wondering about pressures at the moment.
To see if its doable?
Ron

http://35caliber.com/
He is very popular on this site having done 100s of rebores for members.

[samari46]

The pressures you mentioned 46,000 psi should be very safe in the 1891 action. Have two shooters and a few bubbas I picked up at local gun shows. One had a busted extractor and another had a crack in the bolt face. Liberty Tree Collectors does sell spare bolts for both carbine and long rifle and extractors. Don't know what twist you would use and would be kind of dependent on the length of the bullet. Could go with Chilean 1895 action which was originally in 7mm mauser and that should work. Pressures you mentioned should be ok in that action. If you get lucky and find one with a clean bolt face but most I have seen are pitted due to leaking primers. Don't know if your proposed cartridge would work in a Swedish action which was in 6.5x55. Things to consider. I bought a bubba 1895 in 7mm and the guy used a pipe cutter to shorten the barrel. At least the action hasn't been messed with. Just take a slow walk through one of your local gun shows and see what work bubba has done. As long as the action hasn't been messed with then you should be ok. I have a drawer with some actions from bubba's socked away for years. And recently found a beautiful Belgian 7mm mauser barrel I didn't even know I had. Frank

[ronniet]

I appreciate the feedback from all,
Fist the original caliber is 2.992 COAL the 375NE is 2.95 COAL , yes the neck is fatter the rims are same as is the base, Yes I will make up dummy rounds and drill out an old barrel to screw on to it to check feeding. I don't see a problem making it feed, its all done with the magazine lips as the 91 has no rails or lips on the receiver only a ramp.
Mostly worried about the pressures as the 91 like its small ring sisters has no inner shoulder ring, and only 2 lugs on the bolt.


Moleman " bolt thrust"?

Ron
35 Remington shows pressure at 40,000 PSI,
Octagon would be great if you could find one with a breach large enough, most of those are for single shots and levers and are small at the breach. I am thinking 1-12 twist rate?

[Moleman-]

You're supposed to measure the largest diameter inside of the case that the gas would act upon, but most just measure the case head and call it good. So Radius squared times 3.14 x PSI= bolt thrust. The case heads are within a couple thousands, as is the pressure so no big changes.

If you've got access to a mill it takes some time sitting there watching chips come off, but an octagon barrel looks nice.

[ronniet]

You're supposed to measure the largest diameter inside of the case that the gas would act upon, but most just measure the case head and call it good. So Radius squared times 3.14 x PSI= bolt thrust. The case heads are within a couple thousands, as is the pressure so no big changes.

If you've got access to a mill it takes some time sitting there watching chips come off, but an octagon barrel looks nice.

Moleman that is great! I really like the 1891s as far as craftmanship, I usually add a Timney and the swede CP,FP, Spring and shroud and then a Buhler 96 safety,
I cut the mags off flush with the stock and add a leaf spring, homemade follower and hinged floorplate. Usually 2 rounds down and one in the chamber.

I have a table top mill and no indexer or skill to screw up a good barrel. table isint long enough anyway.
I have a new 375cal. unthreaded or chambered barrel in a Medium varmint weight that needs trimming down but I guess I will have to round it.

[CA Dude]

I just tried running a 257 Rob Ack Imp through my 91 and it worked. The 9.5 x 57 case in .001 bigger at the shoulder compared to the Ackley case. My only remaining concern would be will it still cycle with a larger bullet. When I get my dies I will make up a dummy round to check it out.

[Moleman-]

The mill in the pic is a benchtop drill/mill and the length of the barrel was determined by the travel of the table. Had to bolt the indexer and tailstock to a plate and bolt that to the table as the indexer to tailstock length was longer than the table. That was part of the reason there's a 49" bridgeport clone out in the shop now so longer barrels are possible. The bolt right now has a Swedish back half on it, and a redfield peep sight. If it gets drilled and tapped for a scope it'll likely get the bolt sleeve milled for a Wisner side safety.

[ronniet]

wondering if you have to start with a barrel blank or could the medium Varmint weight barrel I have could be milled as octagon measures .75 at the muzzle but is 27" long I plan on using 24" or less. has a nice long breech at 1.250

[ronniet]

CA dude what did the dies cost you and what are the neck size or full length?
Ron

[Texas by God]

If the 9.5x56mm is Mauser magazine length, .476" base, .375" boolits; why isn't it a "superstar" on this forum?[emoji16]

Sent from my SAMSUNG-SM-G930A using Tapatalk

[ronniet]

If the 9.5x56mm is Mauser magazine length, .476" base, .375" boolits; why isn't it a "superstar" on this forum?[emoji16]

Sent from my SAMSUNG-SM-G930A using Tapatalk

Who knows , its a 110 year old cartridge based on the 8mm Mauser necked up to .375 instead or .311 . low pressure on top of that , lower than the 8MM.
A thumper for sure, is why I am making one.Ron

[Texas by God]

Build it; I'll drive up and help you shoot some prairie dogs with it! I'm going to research it now.....

[CA Dude]

ronniet, I purchased a set of dies from CH dies. I paid $116.00 for them including shipping for a 2 die (full length sizing) set. They didn't arrive this weekend. Hope to see them in the next week. This cartridge goes by three different names. Who would have thought? 9.5 x 57 MS, 9.5 x 56 Mauser. I guess that is an example of rounding up or down as one sees fit. Lastly, the British called it .375 Rimless Nitro Express. I have also see it called the .375 Nitro Express Rimless 2 1/2 and the .375 Nitro Express Rimless 2.25.

[CA Dude]

Ronniet, by the way I was sent some really good reloading data from Tedly, a member of this board. I haven't tired it yet. I also looked at some data for the 375 JDJ on the Hornady site. The two cartridges are very similar once you get passed the rim. Been reading where folks have been using 9.3 x 57 loading data as a starting point. As always you got to be careful.

[ronniet]

TbG, let me know anything you find on pressures of it and bolt thrust and anything in 1891 re barrels. Am courious .
CA dude I would like see your load data.
Ron

[Texas by God]

It doesn't seem like a high pressure round at all. You will have to try and procure a factory round to try in your magazine- it beats guessing. I'm wondering where you'll find a chamber reamer? Neat cartridge!
Like a .375 Win for bolt actions.
Sent from my SAMSUNG-SM-G930A using Tapatalk

[CA Dude]

The .375 Rimless sends a 270 grain bullet down range at 2200 fps using IMR 3031 and at 2250 fps with H4895. Original factory loads using 45 grs of cordite sent it at 2150 fps, from a 25" barrel. I think the velocity loss for a shorter barrel will be somewhere between 15 and 35 fps per inch. The best load I can find for the .375 Win slings a 255 grain bullet out at 2045 fps but most loads listed in the Lyman Reloading Handbook, 49th edition show an average of 1,870 fps all with the lighter 255 gr bullet. I decided to get the dies first so I could make some dummy rounds to ship to a reamer maker along with the case diagram I have so the reamer could be made to work with the cartridges my dies will produce.

[CA Dude]

Ron, sent you a PM with the data I have gathered.

[justashooter]

The only problem with the 9.5x56 is the dies may cost more than your completed rifle is worth.

that and the odd.366 diameter bullet availability.

[Uncle Grinch]

Ron,

I searching for more info on your project cartridge, I found this site, however there seems to be a gray area between the 9.5x56 and the 9.5x57.

http://forums.nitroexpress.com/showflat.php?Number=323211

[EDG]

You might want to look at the CIP standaerd for the 9.5X57. It lists the pressure in BARS.

https://www.cip-bobp.org/homologation/uploads/tdcc/tab-i/tabical-en-page72.pdf

3810 bar = 55259 psi


TbG, let me know anything you find on pressures of it and bolt thrust and
anything in 1891 re barrels. Am courious .
CA dude I would like see your load data.
Ron

[Texas by God]

that and the odd.366 diameter bullet availability.

No, 9.3 is .366". 9.5 is .375" if I read correctly. It sounds like a cartridge I would fall for in a correctly set up Mauser!

[EDG]

The 9.5X57 uses a .375 bullet. Its physical limitation may be the lack of a substantial shoulder since it is barely .020 wide which is about like the .35 Rem. shoulder.


No, 9.3 is .366". 9.5 is .375" if I read correctly. It sounds like a cartridge I would fall for in a correctly set up Mauser!

[FrankG]

I have a 9x57 in progress on a 91 mauser carbine action I swapped for . I used a Rem 350 mag barrel chopped threaded and rechambered for 91. Stock is a Boyds . It is going to be quite lite and handy !

[CA Dude]

I received my dies from CH and I have formed some cases. I started with a 400 Whelen cartridge, trimmed it to 2.30. The shoulder of the 400 measured .454. After I full length resized it to the .375 Rimless NE (AKA 9.5 x 57 MS) case the shoulder was reduced to .450 and the neck measured .398. I have seen just one case diagram for this case and it showed a loaded round with a .455 shoulder and a .400 neck. The shoulder on the case is much larger than the shoulder on the 400 Whelen and I haven't had any issues with the headspace on it. I don't think there will be a problem headspacing the .375 rimless NE/9.5 x 57 MS.

[EDG]

The link I posted above goes directly to the official CIP standard drawing for the maximum cartridge and minimum chamber. The dimension P2 for the cartridge is the diameter at the shoulder. That is 11.4 -.20 mm which converts to .448 max and .441 min,
The neck dia is H1 at 10.23mm which is .403 inch.
So worst case the shoulder is (.441 - .403) / 2= .019 per side which is not very much of a shoulder.


I received my dies from CH and I have formed some cases. I started with a 400 Whelen cartridge, trimmed it to 2.30. The shoulder of the 400 measured .454. After I full length resized it to the .375 Rimless NE (AKA 9.5 x 57 MS) case the shoulder was reduced to .450 and the neck measured .398. I have seen just one case diagram for this case and it showed a loaded round with a .455 shoulder and a .400 neck. The shoulder on the case is much larger than the shoulder on the 400 Whelen and I haven't had any issues with the headspace on it. I don't think there will be a problem headspacing the .375 rimless NE/9.5 x 57 MS.

[CA Dude]

236998

While .019 per side isn't very much of a shoulder it is more than adequate. My 400 Whelen when loaded, has a .454 shoulder with a .438 neck measure at the junction of the neck and the shoulder (H1) leaving .008 of a shoulder per side and it works fine. The case on the left is a 400 Whelen. The case on the right is a 9.5 x57 MS/.375 Rimless Nitro Express 2 1/4.

[Binky]

I have my own little love fest going with the 91. I have them from full military to basket case. I like the original 7.65 x 53/54 but also have one in the works in 250-3000 (need to finish the stock) I have also thought about several other calibers (300 savage, 35 Rem, ect.) I will be following this thread with interest!

[Uncle Grinch]

Ron, hows it coming along? Love to see some pictures.

[405grain]

Wow! I've got an 1895 Chilean action that I was considering building as a 35 Remington. I was just about to start ordering a barrel blank & other parts for it this week, and then I saw this thread..... Now I've got some research to do. This sounds like a much better cartridge. Who makes a chambering reamer in this caliber?

[ulav8r]

CH4D.com
icon
Our dies are precision machined from high quality steel, heat-hardened to 59 Rockwell C to a depth of .030" for maximum durability, hand polished for smooth function, and ultrasonically cleaned and coated in a proprietary rust preventative solution.

9.5x56 Mannlicher Schoenauer is an alias for 9.5x57 Mauser / MS. The dies you receive will likely be marked with the more common designation.
7/8" die body diameter.
2 die set includes full length sizer and seater.
Designed for a .375 bullet. The die set includes a .373 expander ball. You can specify a custom expander diameter during ordering.

Die set is $105.71.

[405grain]

Pacific tool and gauge carries the 9.5x57 MS chambering reamer. As per the above post, reloading dies are available. Internet search indicates that people have the least amount of problems when forming the cases from 30-06 brass (which is plentiful), and there are lots of 375 molds to choose from. I ordered a contoured 375 barrel blank this morning. Now I need to start scratching together my nickels and dimes for the other stuff. The pool of knowledge on this site and the way people offer good advise is why I really like it. Building a Mauser in this caliber is going to be so much better than a 35 Remington.

[CA Dude]

I'm going to order my reamer from Manson. I'm going to send him a dummy round so he can match the reamer to the cases I will make. I'm building mine on a Herters U9 action. The action is currently a 308 but it is a intermediate length action and my cases feed without issue. Like you, I'm still scratching together my nickels and dimes.

[Wolfer]

Dang it guys, I don’t need any more guns but now I want to build one of these.

[ronniet]

Sorry, been away as late and haven't gotten back to do any update. I did trade for a new set of 9.5x57 MS dies RCBS in the old cardboard box never used, how lucky can one be? I have all the parts to do the build. I checked the 9.5 rounds in the 91 magazine and reciever.
Used some dummy rounds made to COAL of 2.900 and acted like they were made to use in the single stack magazine. Although didn't have a barrel on it they did feed well from the mag, but the 265gr cast boolits were not completely rounded on the ends and had a flat on them and did want to hang up on the edge of the feed ramp, something that could easily be fixed with a more tilted follower or a more rounded nosed boolit.
I did see EDG's post about the pressure and that is a first I see of the pressure at 55,000psi, from all I have gathered in load books and internet information on the round has it in the 43,000-44,000+ psi range and the pressure is always formost of my concerns when I build something as our builds should be safe as we will not be the only owners of them, as we all will pass them down or get rid of them.
So we need to be sure of the safety of each build.
I started the build because of the large caliber and low pressure I had read about but always safety first.
I am using a DWM 1891 action and bolt, and reduced size magazine that will be cut flush with the stock bottom, will have a hinged straddle type floorplate like that of a 98 Mauser hopefully the rifle will carry 3 rounds.
I am using a 96 Swede FP, CP, shroud and FP spring, a Buehler 96 Safety, a Timney 1891 NOS trigger, Welded low profile Brno type bolt handle , A NOS Bishop semi inletted Mannlicher stock, Hand made Mannlicher nose cap , thru the stock handmade Stirrup type sling swivel like those of the Ruger Internationals, Kick EEZ Nitro pad in case it kicks more than I want to feel.
I have a new CM Barrel which is a 1-12 Twist Medium Varmint profile at 28 Inches but I have turn it down and thread and chamber it yet and cut to length.
I have not found a Reamer as yet or a set of Headspace gauges so this is all on the back burner till I gather the rest of the stuff.

I have one like this already in the original 7.65x53 caliber (because its a great caliber) using the same stuff but on a Sporter length stock.

It uses the original barrel ( no steps) and cut at 25" long. I Rust blue all my guns. I will post a pic or 2 of the 7.65. If I figure out how to do that. The 7.65 is listed at over 56,000 PSI if I am not mistaken?
Ron

[ronniet]

A few more pictures of the 7.65, these were made before I cut the mag flush with the bottom of trigger guard and I mounted a 2.5x7 Weaver Steel tube wide view on it. the tip and caps are African Blackwood and African Paddock wood, The Recoil pad is a Pachmayr Decelerator.

[Texas by God]

That is a very good looking rifle, Ronnie! Personally I would not worry about the pressure with your conversion. A good friend of mine had a custom single shot 1891 with a heavy Sako Barrel in 22 - 250. We fired hundreds if not thousands of high-pressure loads at prairie dogs and targets over a span of decades and never saw any indication of the action failing. Your 9.5 should be lower pressure than that.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[405grain]

Because of the obsolescence, the 9.5x57 MS is going to be a handloading proposition, so too much pressure for some later user shouldn't be much of a problem. I'm gathering up some loading information and other bits of questionable knowledge from the internet. Because the I read that the action for the Mannlicher-Schoenaur is basically an 1888 commission rifle action with a rotary magazine, I believe that the factory pressure for this round would be in the 44,000 to 45,000 psi class. (Maybe the CIP pressure is a proofing load?)
Several suggestions that I read say that it is a lot better forming the cases from 30-06 instead of 8x57. A few people commented that it was even easier to form the cases from 35 Whelen. I thought about this, then thought to myself that it should be even easier to form 9.5x57 cases from 9.3x62 brass. I took a quick look on Graf & Sons, and they sell Prvi 6.3x62 for less that the same brand brass in 30-06. Also, I got a .375 contoured barrel blank from Sarco for $68 shipped (but I get an FFL discount). It looks like a quality blank. I've got a chunk of nicely figured walnut that's long enough for a Mannlicher stock. Now the problem is: If I'm going to go to all the effort to build out a 95 Mauser as a Mannlicher carbine in this caliber, shouldn't the receiver and other metal parts be color case hardened? (See how a little project on the back burner can start growing and growing!) What next - dies, bullet molds, gun parts? My wallet is going to starve to death.

[ronniet]

Just about the same information also that I have gathered from a couple people that have one , books and the internet.
I wouldn't worry so much about the dies just yet, after putting out a request for some on several forums I traded for a new set.
I have not went to a gun show in over 35 years, those of you that do can find them in the dies there for sale as no one really wants a set of them, all are looking for the newest Wham Bam caliber that is out and not many know what the dies are anyway. Only us fool gun hobbyists would want such an outdated caliber. Don't let them fool you that they are rare and in demand and ask for a high price as there is not a line of people wanting them.
As for forming brass I did it with 8mm Mauser brass, didn't ruin any and didn't have to trim any. I still need to fire form it but I used a 41mag expander die and made a new 3 step expander to bring it up to size on the neck. using the lube CH4D sells it only took one push to do it. When I got the 9.5x57 dies I ran them all up into the FL die with the correct size expander set for neck sizing only and they seemed to be on the money, I am sure the shoulder will be in the right shape and place when I fire form them.

I too have a NOS Bishop Mannlicher stock for the 1891 and a 22 " barrel will fit it, I have yet to decide if I want the 375 at 22" or 24, if I go to 24 I will have to find and new piece of wood as I don't want to cut the Bishop off,it would be sacrilegious to do that to a nice piece that has survived for over 30 years.
I saw the ad in Sarco for the 375 barrels and could have kicked myself as I already bought the Shaw for $100.00
Good luck on you guys builds and I hope you post your progress here, I have came down with arthritis in my hips and caused me a lot of pain and bed ridden lately and mine is on the back burner right now.
Ron

[ronniet]

I have to have this put on the back burner a while doing other things , did anyone ever get a Chamber Reamer and headspace gauge?
Ron

[ronniet]

I cut the magazine down on my 7.65 x 53 1891 that is in the pictures above flush with the bottom of the stock, made a follower and leaf spring a straddle floor plate and blued it all and now looks like a Mauser sporter. Holds 3 round if you put on in the chamber.
Has the Buhler Safety, Timney Trigger, Swede FP &Spring, Swede CP, and Swede Shroud , Brno type bolt handle and is still a COC bolt.

[ronniet]

Wears a 2x7 Weaver wide view El paso.

[Texas by God]

Sorry about Arthur Itis visiting you, RonnieT. I hate that guy. If you can, when you can, please post updated pics of that 91. I've never minded the COC feature of the pre 98 Mausers at all. It teaches trigger follow thru as that firing pin ambles it's way to the primer. It makes for a smooth action, too.
And good scope choice, too. Steel Weavers look so good on old blue steel and walnut guns IMO.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[ronniet]

Thanks TBG the Arthur is only a remnant now, all is well till the next rain or cold snap, Unusual I never had a problem before just out of the clear blue it happened.
I will post a few pictures of how I did it along with a why I did it its the same rifle that is in the pics above just without the "hangie down part" now. Try to do that tomorrow.

[ronniet]

243919 243920243921243922243923
This is the 7.65 after I cut the magazine off did away with the internals and make a straddle type floor plate and a follower and spring, holds 2 down and one in the chamber.

[LIMPINGJ]

Very nice looking 91, not the usual chop job sporter conversation.

[Texas by God]

That is very nice. You do great work.

Sent from my SAMSUNG-SM-G930A using Tapatalk

[ronniet]

made the follower out of 16ga building purlin and the floor plate from 14ga purlin. the Mauser spring was carefully and cooley ground down to fint in side the single stack mag. the stops and spring holders were folded and solder on using .010 shim stock

[Uncle Grinch]

Ronnie, hope you can continue this project. I have been checking on this thread trying to see any updates. I finished my 35 Rem on my 93 Mauser or else I would would have leaned towards the 9.5x57.

[ronniet]

Ronnie, hope you can continue this project. I have been checking on this thread trying to see any updates. I finished my 35 Rem on my 93 Mauser or else I would would have leaned towards the 9.5x57.

Yes sir it will happen, I will finish it, I have every part for a full custom 375 NE using the 1891 or I could use the 1936 Mexican. I have both of them feeding it OK and they use the same barrel threads.
I have the best NOS Fajen and Bishop Semi inletted stocks to use, I have the custom parts like firing pins, safeties, triggers, rings bases, the bolt handles are new, barrel is new, I just am finishing up touches on other projects too. I am leaning to the 1891 as I have a Krupp, 1/2 round barrel with rib and express sights that fits the Mexican just right, but its an 8x57 caliber and my action may not be long enough for the 8mm? But I have a great semi inlet Bishop that is a Mannlicher at 22" that would may a nice light weight 375 NE thumper. Only parts I don't have yet is a 375 reamer and gauges, they will eventfully turn up.

[CA Dude]

Well, I got my .375 Rimless Nitro Express (9.5x57 MS) from the Gunsmith about a week ago. It was built on a BSA (Herters U-9) Majestic action. The barrel is 25" long and I scoped it with a Weaver 4x with a crosshair and post reticle.

I have been formed cases from 30-06 brass. That isn't hard but it isn't as easy as running an 06 case into the full length sizer and trimming to length. I loaded 50 round with 235 gr Speer bullets with 46.5 grains of H4895, which is 1.5 grains under max as published by the Mannlicher Collector Association (MCA). I'm guessing that this load will push out at approx. 2300 fps. I loaded up 50 rounds with 270 grain Hornady bullets with 49 grains of IMR4064, which is one grain more the what MCA published. I'm guessing these will push out at approx. 2200 fps. I have fired these without any issues.

Once the weather gets nicer I post some results.

[ronniet]

Well, I got my .375 Rimless Nitro Express (9.5x57 MS) from the Gunsmith about a week ago. It was built on a BSA (Herters U-9) Majestic action. The barrel is 25" long and I scoped it with a Weaver 4x with a crosshair and post reticle.

I have been formed cases from 30-06 brass. That isn't hard but it isn't as easy as running an 06 case into the full length sizer and trimming to length. I loaded 50 round with 235 gr Speer bullets with 46.5 grains of H4895, which is 1.5 grains under max as published by the Mannlicher Collector Association (MCA). I'm guessing that this load will push out at approx. 2300 fps. I loaded up 50 rounds with 270 grain Hornady bullets with 49 grains of IMR4064, which is one grain more the what MCA published. I'm guessing these will push out at approx. 2200 fps. I have fired these without any issues.

Once the weather gets nicer I post some results.

I am glad to hear it, I have all the parts now to go ahead with mine, using the 1891 Argentine as a platform with many custom upgrades to add, I have a reamer and headspace on order from PT&G but have not received it yet.
Am wondering how does its feed from your reciever ? any mods to help it?
I have a set of dummy rounds made up to check feeding but have to get the barrel on it first.
Also wondering about pressures and felt recoil from it.? how does that feel and look like on your cases?
I have a 9.3x62 I made a few years ago and cant bring myself to fire it anymore. The recoil and noise level was just terrible and only fired it 2twice with bruised black shoulder. Using factory Pruvi ammo @ 285 gr.
I will get my 375 Nitro together soon I hope, I had 3 other projects ahead of it and only finish 2 so far.
Good to hear from you update me when you can.
Ron

[CA Dude]

I went out today and shot my loads across a chronograph. My guessamations wasn't too far off. The 235 grain load produced an average of 2,376 fps for a five shot string. This load produced a spread of 118 fps (low 2308, high 2427). The SD was 42.8. In my rifle it produced 22.5 ft. pounds of recoil. Compared to 25.2 ft. pounds of recoil from a 7 pound 30-06 rifle. The 270 grain load produced an average of 2276 fps for a five shot string. This load produced a spread of 37 fps (low 2251, high 2288). The SD was 15.9. In my rifle it produced 26.6 ft pounds of recoil. Compared to 27.8 ft pounds from a 9 pound 300 Win Mag.

The cases for the 235 grain loads indicated zero case expansion. The 270 grain measured .0005 larger than a unfired cases.

I loaded four rounds in the magazine and they all feed without issue. My rifle required no modification to make it feed.

As for how loud it is? Well, it is hard to say. I remove my hearing aides, put in ear plugs, put on my ear muffs and then I talk very loud to everyone.

My rifle was chambered with a Reamer and headspace gauge from PTG. Both are ground to the C.I.P specs. If you have seen the old case drawing from 1910 you will note that the shoulder is shown at .455 in diameter. My reamer produced a .450 shoulder and that cause a very minor issue forming the brass.

My dies were made by CH and they are cut to C.I.P. specs. 30-06 brass can not be just ran through the sizing die and then trimmed to length. The 30-06 when formed in the sizing die results with a shoulder that measures .441 so the case has no resistance against the bolt as it is chambered. You have two options to make the brass so it can be safely fired in you rifle. One expand the neck and body to approx. 43 caliber so that when the case is formed in the die it will have enough shoulder to set the headspace. Or two, when sizing the case don't push the shoulder back so far. In my case I put a .030 feeler gage between the shell holder and the die, then tighten the die down against the feel gage. The first case could not be forced into the rifle enough to close the bolt. I kept doing this same process with thinner feeler gages until I had a .021 gage between the shell holder and the die. When set up like this I could close the bolt on the formed case. I then sized all my brass with this set up. The neck measured only .328 in length. When I fired the round it came out with a .350 length neck that matches the old case drawing.

Overall, I think it will be a very good round for hunting Middle Weight to Light Heavy Weight, non-dangerous game. My 270 grain loads still has 2080 ft. pounds of energy at 200 yards. I think I could harvest just about any animal I'm likely to run across in the woods of Arkansas.

[samari46]

How about the 9.3x57??. Make brass form 8mm cases. Open the necks to 375 then slowely resize in a 9.3x57 die but leave a slight shoulder so when you close the bolt you get a slight crush fit. Headspace wasn't all that great. 286 grain round nosed bullet at 2100 -2200 feet per second and with about 45 grains IMR 4895. pressures are low about 44.000 psi so no barn burner. I measured the twist on mine and get 1x14".You can go slightly faster with the twist say 1x12" Really nothing fancy. Frank

[ronniet]

I went out today and shot my loads across a chronograph. My guessamations wasn't too far off. The 235 grain load produced an average of 2,376 fps for a five shot string. This load produced a spread of 118 fps (low 2308, high 2427). The SD was 42.8. In my rifle it produced 22.5 ft. pounds of recoil. Compared to 25.2 ft. pounds of recoil from a 7 pound 30-06 rifle. The 270 grain load produced an average of 2276 fps for a five shot string. This load produced a spread of 37 fps (low 2251, high 2288). The SD was 15.9. In my rifle it produced 26.6 ft pounds of recoil. Compared to 27.8 ft pounds from a 9 pound 300 Win Mag.

The cases for the 235 grain loads indicated zero case expansion. The 270 grain measured .0005 larger than a unfired cases.

I loaded four rounds in the magazine and they all feed without issue. My rifle required no modification to make it feed.

As for how loud it is? Well, it is hard to say. I remove my hearing aides, put in ear plugs, put on my ear muffs and then I talk very loud to everyone.

My rifle was chambered with a Reamer and headspace gauge from PTG. Both are ground to the C.I.P specs. If you have seen the old case drawing from 1910 you will note that the shoulder is shown at .455 in diameter. My reamer produced a .450 shoulder and that cause a very minor issue forming the brass.

My dies were made by CH and they are cut to C.I.P. specs. 30-06 brass can not be just ran through the sizing die and then trimmed to length. The 30-06 when formed in the sizing die results with a shoulder that measures .441 so the case has no resistance against the bolt as it is chambered. You have two options to make the brass so it can be safely fired in you rifle. One expand the neck and body to approx. 43 caliber so that when the case is formed in the die it will have enough shoulder to set the headspace. Or two, when sizing the case don't push the shoulder back so far. In my case I put a .030 feeler gage between the shell holder and the die, then tighten the die down against the feel gage. The first case could not be forced into the rifle enough to close the bolt. I kept doing this same process with thinner feeler gages until I had a .021 gage between the shell holder and the die. When set up like this I could close the bolt on the formed case. I then sized all my brass with this set up. The neck measured only .328 in length. When I fired the round it came out with a .350 length neck that matches the old case drawing.

Overall, I think it will be a very good round for hunting Middle Weight to Light Heavy Weight, non-dangerous game. My 270 grain loads still has 2080 ft. pounds of energy at 200 yards. I think I could harvest just about any animal I'm likely to run across in the woods of Arkansas.

CA Dude ,
glad you made the rifle and I commend you in the collection of the data,
I copied all your data to use when I finish up my 375 Nitro. Thank you
I think it would be a great addition to the calibers
Ron

[CA Dude]

Ronniet,

I shot my loads for groups yesterday. My rifle seems to like the 275 grain bullet. 49.0 grains of IMR 4064 produce 1 1/4" groups. The 235 grain loads not so well; 2 to 2 1/2" groups. If I had a different reticle I think I could bring the groups size down some. The post covers about 2" at 100 yards. I think that is fine for hunting but a little course for grouping.

I have checked out the 375 Raptor cartridge and they are getting the best velocity by using Rel 10x. I ran 10x through Quickload and I'm going to give it a try. I have no intention of running to the same pressures of the 375 Raptor even though my rifle could handle it. According to the Prowley Computer 49 grs. of IMR 4064 produces 51,000 psi (44,900 CUP). The max load as given by MCA of 48 grs of IMR 4064 produces 49,000 psi. I was a little surprised that Quickload and Prowley came in very close when comparing this load.

I'm looking forward to using some cast bullets and my paper patched bullets soon.

CA Dude