shooting a 7mm Mauser Remington Rolling Block Model 1902

I just bought a nice looking Rolling Block in 7mm. The gun shop I bought it from told me it was a strong action and it was good to go, and they sold me a box of Winchester Super-X 7x57 Mauser to go with the rifle. While doing research online to find out what model I had, I came across info which said the 7mm is not safe in this gun, due to excessive headspace issues caused by the 7mm cartridge being a bit longer at the turn of the 20th Century than it is today. I also read that today's 7mm Mauser factory ammo is too hot for the action, regardless of headspacing.

I also bought George Layman's book, which was very helpful in identifying my rifle as a Model 1902.

I bought some Plasti-Gauge and measured about 4.5 to 5 thousandths headspace between the case head and the rolling block face, with the block closed and the hammer down. I'm told max allowable here is 0.003".

I thought this round headspaced on the shoulder, and so I thought perhaps I could decrease headspace by moving the shoulder forward a bit, so I took a 30-06 case and ran it through my 7mm die. I ended up with a weird looking, very long neck 7mm case with the shoulder moved forward about 1/16". However, the case was about 1/4" too long to go into the chamber, so it's apparently headspacing on the case mouth, rather than the shoulder, as I'd thought it did. I haven't yet tried trimming the case neck back to get the headspace I am seeking. Perhaps some more tinkering/experimenting there...... Does anyone know for sure where this round headspaces?

In George Layman's book, he unfortunately didn't go into much detail about it or the alternatives, but he explicitly made a highlighted point of saying the 7mm rifles should not be shot at all (page 31). So, while it seems like a nice rifle in great original shape, I am thinking perhaps I should take it back to the gunshop for a refund. I guess the only other option would be to send it out for rechambering/reboring in a rimmed caliber. Your thoughts on that? The rimmed calibers don't have the headspace issue? I'm looking at a couple older ones in 43 Spanish now.

If you just resized a 30-06 into a 7x57 (with the shoulder moved a little forward) and you didn't trim the case to overall length, of course it's not going to chamber. The case mouth was hitting the end of the chamber which a proper fitted case isn't supposed to. Trim your 30-06 case formed into a 7x57 to the same length as a factory case, or to the trim length given in loading manuals. Then try your case in the chamber. If it's still too long resize the case shoulder back a tiny bit at a time and keep trying the fit. You will eventually get the proper fit with it head spacing on the shoulder without that excessive headspace. You only have to do the reformed 06 cases once. After they've been fired they'll be 7x57's except with the 30-06 nomenclature stamped on the case heads. Also your 06 cases being a little thicker you will want to start your loads low and work up. They have less internal capicity then thinner 7x57 cases and that raises the pressure.

Pull your factory loads,reload to about 35,000psi level and shoot your gun.A few thou extra in the "headspace" wont hurt anything.The reason your reformed cases wont fit is springback of the brass after sizing.In short 7mm Mauser has more case taper that 30-06.The Mauser definitely headspaces on the shoulder.Your gun hasnt survived 115 years because it was too weak .

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Originally Posted by john.k

Pull your factory loads,reload to about 35,000psi level and shoot your gun.A few thou extra in the "headspace" wont hurt anything.The reason your reformed cases wont fit is springback of the brass after sizing.In short 7mm Mauser has more case taper that 30-06.The Mauser definitely headspaces on the shoulder.Your gun hasnt survived 115 years because it was too weak .

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The reason his cases didn't fit is because he didn't trim the long necks off after forming from 30-06!

I have a 7x57 RB and a H&R 7x57.
I fired one round in each and then measured headspace of extracted cases and compared to values on the factory round used.
The RB was longer-not going to publish how much, it was just longer, H&R was more 'standard'.
Remainder is for the RB.
I then cut some 270W brass to length a little, .010", over what I thought would be needed.
The FL sized starting with the sizing die above the shell holder a little over the amount of excess HS.
Each revolution of sizing die is approximately .0715", so gauge needed lengthing using this as guideline.
ie 1/8 revolution approx. .0088"
I then resized case, tried it in RB screwing die down little by little until breech would just close on case.

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Originally Posted by kywoodwrkr

I have a 7x57 RB and a H&R 7x57.
I fired one round in each and then measured headspace of extracted cases and compared to values on the factory round used.
The RB was longer-not going to publish how much, it was just longer, H&R was more 'standard'.
Remainder is for the RB.
I then cut some 270W brass to length a little, .010", over what I thought would be needed.
The FL sized starting with the sizing die above the shell holder a little over the amount of excess HS.
Each revolution of sizing die is approximately .0715", so gauge needed lengthing using this as guideline.
ie 1/8 revolution approx. .0088"
I then resized case, tried it in RB screwing die down little by little until breech would just close on case.

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Exactly what I explained!! The OP, from what I read, didn't trim his new formed case to length.

Yes, I had only done the first step as an experiment, just to check feasibility, as opposed to jujst returning the rifle to where I bought it. After getting the concept confirmed by the helpful post from vzerone, I went ahead and did the rest. Even though I was really just winging it, as a test, and doing it all by eye, it quickly went very well. I cut the OAL down to 2.250", figuring the whole chamber was a bit long (published OAL is 2.235"). Case dropped right in, headspace was just a hair too long. Then I did another 1/8 turn on the die. Bingo! Case dropped right in, block closed up just enough to let the hammer fall. I didn't anneal anything before doing this. Cases look pretty good, with shoulder about 1/16" forward of a standard 7x57 case. I'll try annealing first, in my next experiment, to see how that goes. I probably should also Cerrosafe the chamber, to see if I should make the OAL any longer. Then I'll load these cases up with some 5477 reduced loads & fire form them.

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Originally Posted by brian1

Yes, I had only done the first step as an experiment, just to check feasibility, as opposed to jujst returning the rifle to where I bought it. After getting the concept confirmed by the helpful post from vzerone, I went ahead and did the rest. Even though I was really just winging it, as a test, and doing it all by eye, it quickly went very well. I cut the OAL down to 2.250", figuring the whole chamber was a bit long (published OAL is 2.235"). Case dropped right in, headspace was just a hair too long. Then I did another 1/8 turn on the die. Bingo! Case dropped right in, block closed up just enough to let the hammer fall. I didn't anneal anything before doing this. Cases look pretty good, with shoulder about 1/16" forward of a standard 7x57 case. I'll try annealing first, in my next experiment, to see how that goes. I probably should also Cerrosafe the chamber, to see if I should make the OAL any longer. Then I'll load these cases up with some 5477 reduced loads & fire form them.

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GREAT! Glad I explained it well enough. Now here's what you can do to check that chamber length and not have to do a cast of it. Make another case like you did except this time leave the neck long and trim it back a little at a time till it just fits. That's the length of the chamber. You will want to trim your cases a tad shorter then that as you never want the case mouth up again the end of the chamber for safety reasons. Wow! So the shoulder on the case that fits with no excess headspace is 1/16th of an inch longer then the shoulder on the 7x57. That's some headspace that rifle has. You'll be safe now and BTW those rifles shoot very very good.

Hey brian don't anneal them dead soft.

American 7mm ammo is loaded light in dererence to the 93 Mausers and Rem RB. Pad it, tie it to a rest or a tire, string the trigger from shelter. Shoot it and inspect your fired case. It will probably show a proud primer. Assuming the gun didn't blow you can shoot those shells for brass to custom fit your chamber.

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Stay away from imported 7x57 ammo for that RB. It is loaded hotter by a bit than American ammo.

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Originally Posted by Texas by God

American 7mm ammo is loaded light in dererence to the 93 Mausers and Rem RB. Pad it, tie it to a rest or a tire, string the trigger from shelter. Shoot it and inspect your fired case. It will probably show a proud primer. Assuming the gun didn't blow you can shoot those shells for brass to custom fit your chamber.

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TBG if he is getting rid of all the excess headspace that he had why would the primer be proud?

If I understand it correctly, there's not enough back thrust to reseat the primer with the long headspace. The reason some CB loads need to have the flash hole enlarged in the brass to prevent proud primers. I've had this happen on some Surplus rifles and the cure was fire formed brass and in some a wee bit more powder. IME;IMO; YMMV. I've never owned a Rolling Block,(Yet) but the 7mm is proofed for smokeless pressure and Remington quality built. Forming cases from '06 family may very well require neck turning to prevent high pressure from tight necks. Necking down 8x57 may give you the second shoulder needed to custom fit the case to the chamber.
Pics, please. Good luck.

Brian measured the headspace with Plastigage,and reported it to be .005",a tad longer than allowable ,but still safe.Now by some magic it has ballooned out to .0625" an increase of some 12 times.Ok so he didnt trim the case,something I find incredible.He used Plastigage,so he must have a passing acquaintance with mechanical matters,surely he could tell the lengths of cases were nearly1/4" different.I dont really know why I bother replying to questions that are a set up.

Fireforming might help with excess headspace, but there's another issue that can't be addressed on a Rolling Block by fireforming. The design of the "rolling breech block" means if the gun is loose, then the breech block is not square to the bore, and will sit at a slight angle to the bore. That means every cartridge fired in it will end up with the case slightly bent at the head area, just above the rim. The result will be cases that will only fit in the chamber at whatever direction they were fired, and if turned 180 degrees when loaded, they wont fit and allow the breech block to close.
I've seen this happen more than once on old Rolling Blocks. One can put an index mark on the rim and simply make sure to always keep the mark at 12 o'clock, if you want to just have fun shooting it. The fix I use is to have a welder tig weld the bottom of the breech block to build it back up, and then stone it down until the headspace isn't an issue and the block is square to the bore.

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Originally Posted by Texas by God

If I understand it correctly, there's not enough back thrust to reseat the primer with the long headspace. The reason some CB loads need to have the flash hole enlarged in the brass to prevent proud primers. I've had this happen on some Surplus rifles and the cure was fire formed brass and in some a wee bit more powder. IME;IMO; YMMV. I've never owned a Rolling Block,(Yet) but the 7mm is proofed for smokeless pressure and Remington quality built. Forming cases from '06 family may very well require neck turning to prevent high pressure from tight necks. Necking down 8x57 may give you the second shoulder needed to custom fit the case to the chamber.
Pics, please. Good luck.

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He's not going to have long headspace, he's sizing 30-06 cases with the shoulders moved forward a bit. That eliminates the long headspace he had. He'll adjust his sizing die to not push that new shoulder position back.

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Originally Posted by john.k

Brian measured the headspace with Plastigage,and reported it to be .005",a tad longer than allowable ,but still safe.Now by some magic it has ballooned out to .0625" an increase of some 12 times.Ok so he didnt trim the case,something I find incredible.He used Plastigage,so he must have a passing acquaintance with mechanical matters,surely he could tell the lengths of cases were nearly1/4" different.I dont really know why I bother replying to questions that are a set up.

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John he didn't trim the long neck left by sizing 30-06 to 7x57. So now he has done that and he'll next be trimming the necks just shy of the chamber limit. By moving the shoulder forward using 30-06 cases he no longer will have that .005 headspace, so it's safe.

Safe is good, but still need to be concerned about the angle of that breechblock with having to make up for that much headspace.

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Originally Posted by vzerone

He's not going to have long headspace, he's sizing 30-06 cases with the shoulders moved forward a bit. That eliminates the long headspace he had. He'll adjust his sizing die to not push that new shoulder position back.

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No, I was referring to using the ammo he had in 7x57 instead of forming from 06 family. I understood what you were saying.

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Originally Posted by Texas by God

No, I was referring to using the ammo he had in 7x57 instead of forming from 06 family. I understood what you were saying.

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Yes absolutely with what you are talking about then. From what I and friend know that most all of those Rolling blocks had drastically oversized chambers in just about all dimensions. I know the one poster here keeps referring to the huge amount of headspace and the fired case being crooked, but all the Rolling blocks we've examine have this excess headspace do the large chamber dimensions I just mentioned including large from the head of the case to the datum line. I believe the OP will be okay forming his 06 brass correctly. I'm sure we'll find out soon.

Couldn't a person just expand 7x57 brass up to 30 caliber then size it back until it chambers. That sounds easier to me. I have 3 of them that were too nice to use as donors that I haven't had time to play with yet. I wasn't aware of the head space problem. So I'll need to plan accordingly when I start playing with them. Thank you for the heads up.
WW