I am looking to try a wildcat like a 30 caliber made on the full length 9.3x74R case Trying to get velosity close to 30-06 but keeping pressure below 45,000 for use in a rolling block Would using a larger case reduce pressure and still get a higher speed

7.62x54 ... the end

jeffe

Or how about a .30-40Kraig or maybe a .303 necked down to .308?

I was looking for better velocity than the 30-40 can give or 303 can give Was looking to at least give 30-06 levels but the pressure needs to be below 45,ooo

You'll need to consider the case diameter as well as the pressure. Under pressure, the case acts as something of a piston, and the thrust increases with the square of the case diameter.

Actually, I've been wondering about the very conversion you mention. I have a No.5 replica on order from Lone Star, but the project is on hold while I ruminate over chamberings.

According to estimates by QuickLOAD, you can get 2400 fps with 220 gn bullets with powders as slow as Reloder 22, this from a 26" barrel. The calcualtions are based on a case of 80 gn capacity, so it would require the shoulder to be moved out and/or forward. One edition of Cartridges of the World showed just such a wildcat developed for Meacham and their High-Wall replicas. The operating pressure was higher than 45 ksi, though.

Frankly, I'm not sure the RB action is good for a steady diet of 45 ksi ammunition. There is an ongoing series on this subject in the Single Shot Exchange, written by an older RB user and collector. The owner of Lone Star feels 44 ksi is the limit, and while he doesn't seem concerned with case diameter, I certainly am.

I intend to aim for the mid 30's. To keep the power up, I'll have to go for a bigger bore, of course. The .35 WCF loaded down a smidge is a possibility.

If you want to push it, the classic .30 Super Flanged Magnum is 46 ksi (CIP piezo rating) with a head diameter about that of the .45-70. I wouldn't shoot it myself, but you can probably send 220 gn @ 2500 fps with it -- if the gun holds together. You'd have to go about as slow as Reloder 25, though.

again,
7.62x54 ..

case capacities h20
7.62x54 64gr
30-40 58gr
303 56gr
303 improved 59.70
30x444 (309 jdj) 62
30 Flanged NE Purdey 58gr
303 jeffery magnum 73.50

only the 303 jeffe is larger... and I aint ever seen that brass offered, period.

jeffe

The 7.62x54R is a worthy cartridge, but it (1) has less capacity than the .30-06, so it must operate at higher pressures for the same performance, (2) has a higher standard (ie. CIP) operating pressure, above our friend's limit, and (3) can be confused with the 7.62x53R, which uses a slightly different diameter bullet, and is spec'd at an even higher pressure.

The .30 Super Fl. Mag. (H&H) has a case capacity of about 90 gn, well above Purdey's Fl. Mag., but for the RB, I'm leary of its diameter.

Another thought is to run 9.3x74R brass into a .30-06 die, and then trim it back for a case length of 2.4" to prevent chambering of factory .30-06 cases. Have the reamer cut for the shorter case length and for a chamber throat allowing the 220 gn RN to be seated only 0.30" deep and let fly from a 26" tube. Ye Olde Powley Computer suggests 2300 fps can be obtained at Krag pressures. This way, you avoid the cost of custom dies, needing only a custom reamer.

asdf,
the 7.62x54r and 53r (russian and finnish) are exactly the same round with different names, though saami and cip slightly differ on top pressure . it's around 55k psi.. something like 45k cup...

it's easy to get mimxed up with the 7.65x53 argentine, though, but the rounds aren't interchangable


remember, ALL commerical 7.62x54 ammo (not machine gun ammo) is designed to be perfectly safe to fire in 1891 nagant rifles. all of it. that's a 45k action, on a good day

the 30-06 is 67-69 gr of water (depending on maker)

the 9,3x74 is a rather slender case, and something like 82 gr with a .366 bullet, that it will loose some when necked down.

the 30-06 picks up ~3gr with going to 35, so let's say the x74 would loose 4 grains going to 30 caliber...

or 18 grains more powder room then the 7.62x54

and you don't have a wildcat, or $$$$ on brass..

just load down a bit for safety

jeffe

quote:

Originally posted by asdf:
The 7.62x54R is a worthy cartridge, but it (1) has less capacity than the .30-06, so it must operate at higher pressures for the same performance, (2) has a higher standard (ie. CIP) operating pressure, above our friend's limit, and (3) can be confused with the 7.62x53R, which uses a slightly different diameter bullet, and is spec'd at an even higher pressure.

The .30 Super Fl. Mag. (H&H) has a case capacity of about 90 gn, well above Purdey's Fl. Mag., but for the RB, I'm leary of its diameter.

Another thought is to run 9.3x74R brass into a .30-06 die, and then trim it back for a case length of 2.4" to prevent chambering of factory .30-06 cases. Have the reamer cut for the shorter case length and for a chamber throat allowing the 220 gn RN to be seated only 0.30" deep and let fly from a 26" tube. Ye Olde Powley Computer suggests 2300 fps can be obtained at Krag pressures. This way, you avoid the cost of custom dies, needing only a custom reamer.

You still end up short of 30-06 velocity, though. More like 308. For all that work, I would rather neck 7 x 65R up to 30 cal.

If the RB took 50-70 I don't see a problem with the 300 Fl except brass is a bitch. It's the barrel shank that does the hard work and it seems enough to me. Of course, there is always the 30R Blaser? Seems the closest to the spec without wildcatting.

I think necking down & imp. the 9,3x74R is a viable idea. I have a .338x74Keith, necked down & imp. 9.3x74R. I run it on the warm side in a Ruger #1, getting 2800fps w/ a 225gr bullet w/ little fuss. RWS brass is the way to go as Norma is thinner in the web & shows head seps. after 5-6 firings.
Loaded w/ a slower powder like H4831sc or RL22, pressures would be quite low w/ 180 & 200gr bullets.

quote:

It's the barrel shank that does the hard work and it seems enough to me.

I agree the shank seems enough, but I disagree that the shank does the hard work. I have dimensioned drawings for the RB, and I did a most basic stress analysis of the breech. My numbers suggested to me there is very little room to spare there with regards to case thrust. When I get back to the US, I'll get a better PC and some proper finite element stress analysis software to apply to the problem, but until then, I will not load an RB hot. In the SSE articles I mentioned, the author strongly urges one not to fire modern factory ammo in the old smokeless RBs. Also, the owner of Lone Star Rifles reported a 7 mm military model disintigrating on him when using factory ammo, although it was the receiver ring that failed, not the breech.

I must admit I have read Remington made rolling blocks in 7.62x54R for the Russians around the time of WW-I, and if so, the action may be stronger than I estimate.

Hey jeffe, thanks for explaining the difference between the x54R and x53R. I have CIP listings, and I had wondered what was the origin of these two separate entries. The CIP lists a slightly smaller bore for the x53R, but in practice that may not have been so.

asdf,
i've measured slugged nagants from .307 to .314...

the finnish are always on the smaller end.. i think they wore out the button then sold them to the russians..

.3105-.311 is "perfect".

cheers
jeffe

Just a thought; Short ream ( Maybe .050" )a .300 H&H so it can not chamber factory ammo Or just go all the way with a standard .300 H&H. If you go the short stroke finish the belt section off by hand on the lath.

You can use a cut off set of H&H dies. 06 balistics at lower pressure, no reamer charges, no exhorbitant die costs, brass plentifull and all your loading data available. roger

quote:

7.62x54 ... the end

I'll fifth this suggestion. It's as close to perfect for the job as described as you're going to get.

hi
what about 0,30 blazr r it is more than 3006 and you can get cases from RWS.
regards
yazid

what pressure is the 7.62x54 . I had been told to stay under 45,000 but had seen someone mention a phil sharp article stating loads in the 60,000 range Is there any real data as to the actual strenght of a rewly made rolling block like the Lone Star or navy arms pedersoli actions
argolee

quote:

Originally posted by asdf:

quote:

It's the barrel shank that does the hard work and it seems enough to me.

I agree the shank seems enough, but I disagree that the shank does the hard work. I have dimensioned drawings for the RB, and I did a most basic stress analysis of the breech. My numbers suggested to me there is very little room to spare there with regards to case thrust. When I get back to the US, I'll get a better PC and some proper finite element stress analysis software to apply to the problem, but until then, I will not load an RB hot. In the SSE articles I mentioned, the author strongly urges one not to fire modern factory ammo in the old smokeless RBs. Also, the owner of Lone Star Rifles reported a 7 mm military model disintigrating on him when using factory ammo, although it was the receiver ring that failed, not the breech.

I must admit I have read Remington made rolling blocks in 7.62x54R for the Russians around the time of WW-I, and if so, the action may be stronger than I estimate.

Hey jeffe, thanks for explaining the difference between the x54R and x53R. I have CIP listings, and I had wondered what was the origin of these two separate entries. The CIP lists a slightly smaller bore for the x53R, but in practice that may not have been so.

I would not be surprised if the heat-treat was changed when that action transitioned from BP to smokeless. The test of the breeching mechanism is to roll a fired round on a flat surface, I'm told. If there is a noticible wobble in the rim you are pushing the action farther than the block can stay locked.

Also, there are threads here about the differences between the original German 7x57 case dimensions and the US SAMMI adopted dimensions that raise serious concerns about shooting US ammo in an older 7 MM chamber. They don't get much older than the Remington RB. That blow-up may be specific to that caliber.

argolee: With regard to pressure be mindful of CUP vs. true psi. Older data is nearly always in what today is called CUP, but was then usually just called "psi." In the pressure range we're discussing, CUP is usually between 5 and 10 thousand psi below true. It is psi that will break a gun, not CUP. A list of cartridge pressures can be found here.

My notes include Phil Sharpe's comments on the rolling block, and I'll paste these notes here:

quote:

In the supplement on the 7x57: It was being chambered in the US by the
early 1890s. The US ammo. is kept to about 39,000 due to old single shots
such as the rolling block. However, German ammo goes to 55,000. He took an
"old Remington-Rider" and shot 4 proof loads of 70,000 followed by 200 rds
of the German 55,000, and the gun was fine afterwards.

These by far are the most agressive loads I've noted. Given the date of the book (1953), these pressures should all be CUP. I'm more than a little skeptical, since I doubt factory loads in Europe were really 55,000 CUP. The CIP standard is 49,000 CUP. I'll note that even though Remington was making military rolling blocks until WW-I, they never offered (to my knowledge) them in .30-06, a 50,000 CUP cartridge.

On the other hand, on the web I've come across listings for Pedersoli's in .30-40, an original chambering. These should have been proofed to CIP standards, and those are a trifle hotter than the SAAMI specs, and are 41,000 CUP / 47,000 psi.

tiggertate's comments on case deformation I've seen before. Given such deformation and the fact there is little protection in a rolling block from the gases of a case rupture, I will be keeping my pressures (and diameters) on the modest side.

All wildcats here:

.30-35 Win (35 Win necked down)
.30-.405 Win
.30-348 Win Imp
.307 Win Imp

Just some brain-farts I can up with.

MM

Pop over to David White's site, he has wildcats based on the 9.3x74 with an improved shoulder,, he does them up on H&R and Encores.. Mite be worth a look

quote:

Originally posted by argolee:
I am looking to try a wildcat like a 30 caliber made on the full length 9.3x74R case Trying to get velosity close to 30-06 but keeping pressure below 45,000 for use in a rolling block Would using a larger case reduce pressure and still get a higher speed

Why don't you take simply the 30R Blaser? That is class a Kalieber, with which you can use 30,06 a barrel with 10"/1 twist and which have same gas pressure. The power of the cartridge lies between the 30,06 and the 300WinMag. You kan us all .30 bullets betwin 130 and 200 grains.

The pressure of the .30R Blaser is too high for the RB. Also, the case head is a bastard size, so if the supply of .30R brass ever dries up, you'll have a heck of a time forming new cases, and let's face it, the .30R isn't exactly topping the sales charts.

Virtually no protection for a ruptured case. And they rupture much easier in an RB where the block can roll back and expose a small portion of web, like an unsupported 45 ACP. This action is old in design regardless of materials and not to hot rodded. I would rather get a repro high wall or some-such if I wanted modern performance.

Get an old swede RB m/1889 in 8x58 Rimmed Danish, as all bolts are reinforced for the relatively modern cartride. Keep the caliber or rebarrel to .30 Krag.
To read: http://www.pettsons.net/remington.html
A picture of a sporterized Swede: http://www.pettsons.net/hvapics/8x58_sporter.gif

Regards,

Fritz

I would take a look at the 30-40 Krag Ackley Improved. EABCO has some info on it for their singleshot rifle which can't take higher pressures than a T/C Contender. Done right you can fireform with factory ammo then reload up to Ackley velocities. Just a thought...RW

just an answer to one of the posters re. strength of Navy Arms modern made rolling block actions..
Plenty strong in my experience. I had one made up for a .50 Alaskan, shot 700 gr. hard cast gas checked bullets at about 1750 fps. (25 inch barrel). There's an article in "Big Bore Rifles" that discussed the good strength due to modern steels, and closer tolerances. Fear not with the newly made Navy Arms Rolling Block actions!
Best Regards, Tom