shooting a 7mm Mauser Remington Rolling Block Model 1902

[brian1]

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.

[vzerone]

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.

[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 .

[vzerone]

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 .

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

[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.

[vzerone]

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.

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

[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.

[vzerone]

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.

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.

[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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[Texas by God]

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

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[vzerone]

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?

[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.

[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.

[marlinman93]

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.

[vzerone]

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.

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.

[vzerone]

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.

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.

[marlinman93]

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

[Texas by God]

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.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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[vzerone]

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.

[wwmartin]

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

[vzerone]

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

Yes you could do that. It does work harden the brass though. Being the Rolling Block chambers are oversized the 30-06 brass is the better case to use because it is slightly thicker especially in the neck. That's because some of the new neck is from shoulder area of the 06 case.

[Reverend Al]

Yes you could do that. It does work harden the brass though. Being the Rolling Block chambers are oversized the 30-06 brass is the better case to use because it is slightly thicker especially in the neck. That's because some of the new neck is from shoulder area of the 06 case.

That's what I did with my 7x57 South American Rolling Block ... I used a tapered expanding mandrel to open the 7x57 brass up to about .30 calibre and then slowly adjusted the sizing die down until the block would just close. I've test fired it once so far with good results and I load it down appropriately to ensure that the pressures are sensible for this old rifle. The other thing that you will likely encounter (like I did) is that it also has an extremely long throat. I am loading 175 grain semi-spitzers and round nose bullets and have them seated out until they are barely held by the neck of the case. They are still well off the throat, but even though the bore is moderately worn in my rifle it shot amazingly good groups at 100 yards. (4 shots went into a nice round group of about 1 1/2" / 2" and one flyer that was about 2" left from the group ... but it was also the first round fired from the cold, clean barrel). Fit some brass to your chamber's shoulder length, load some 175 grain bullets at very moderate pressures, and enjoy that old gun! (I was loading 34.0 grains of IMR3031 and IMR4064, but of course you should work up to that if you want to try duplicating my loads. For me it shot equally well with both powders.)

[vzerone]

That's what I did with my 7x57 South American Rolling Block ... I used a tapered expanding mandrel to open the 7x57 brass up to about .30 calibre and then slowly adjusted the sizing die down until the block would just close. I've test fired it once so far with good results and I load it down appropriately to ensure that the pressures are sensible for this old rifle. The other thing that you will likely encounter (like I did) is that it also has an extremely long throat. I am loading 175 grain semi-spitzers and round nose bullets and have them seated out until they are barely held by the neck of the case. They are still well off the throat, but even though the bore is moderately worn in my rifle it shot amazingly good groups at 100 yards. (4 shots went into a nice round group of about 1 1/2" / 2" and one flyer that was about 2" left from the group ... but it was also the first round fired from the cold, clean barrel). Fit some brass to your chamber's shoulder length, load some 175 grain bullets at very moderate pressures, and enjoy that old gun! (I was loading 34.0 grains of IMR3031 and IMR4064, but of course you should work up to that if you want to try duplicating my loads. For me it shot equally well with both powders.)

The important is that you got the brass to fit better, got it shooting, and enjoyed shooting it. Can't ask for more then that. It's not the only rifle with an extra long throat that gives us reloading headaches. We have to remember that many of the old military rifles used exceptionally long heavy bullets so they were thus throated for them. Trouble is when we want to load lighter shorter bullets.

[Texas by God]

I've learned a lot this thread. And brian1 where are those pics?

[brian1]

Thanks for all the insights & info. The original "neck way too long" thing was just an initial experiment to see if I could push the shoulder back, having never tried anything like that before. That was just in lieu of either returning the gun or sending the barrel out to be rechambered. I looked in my books and picked the 30-06 as a caliber that I had buckets of brass for and had the same case head dimensions.

I figured it would be better to try to size down than to stretch the brass by sizing up.

I did as suggested earlier in this thread. I trimmed to about 0.015" longer than the "trim-to" length, then set my shoulder back. I was resizing old WWII 30-06 brass, which may have been thicker and tougher than newer brass. In the initial experiments, I was not annealing. I found that, due to brass springback, if I set the die all the way down for "normal" resizing, I ended up with the shoulder positioned at what looked to be about 1/16" forward of the 7mm brass. I set it so the block would just barely close and the hammer would completely fall.

In later experiments, I annealed first, and that made it go even easier. It also resulted in a bit less springback, which was OK because, probably due to wear between the hammer and block, I felt perhaps the block should be allowed to close a bit more, to address the possible "block face not perpendicular to the case head" problem if the block was closed only enough to allow the hammer to barely drop.

Once I got my anneal time set, using Tempilac (5 seconds in my torch), I annealed before sizing. I also started using some once-fired Remington brass, for more consistent results in resizing than the mixed old milsurp brass.

After I got all that set, then I made one with the shoulder right where I wanted it, but with a really long neck, and then started trimming the neck until the block would just close so the hammer would fall all the way without binding against the block. My 7x57mm Mauser brass is 2.225" OAL. Trim-to is 2.235". My initial cases were set to 2.250". By starting at about 2.290" and working down, I found that my zero-gap distance was with OAL of 2.266" with the milsurp brass, and 2.264 with Rem brass. I'm not sure why the difference in max OAL between milsurp brass and Remington.

I'm not sure what gap I should leave between the case mouth and the end of the chamber. Any opinions? I'm thinking something like 0.010". Maybe none at all for fireforming?

Because I had my little chop saw all configured for the cuts, I went ahead and cut up 60 of my Remington 30-06 brass, deburred them, and left them in the tumbler overnight. Next, I will anneal them, resize them, set final OAL, and then fire-form them for the final product.

Here is a picture of the initial experimental cases. Left to right are 7x57mm Mauser, 1953 mil brass, initially formed cold, later reformed after annealing, set to 2.250" OAL, 1942 mil case, same as 1953, then a 1953 set to 2.266" OAL.
207687

For fireforming, I can either load up what should be a pretty light load, like about 18 grains of AA 5744 under a 145 grain bullet or 20 grains of IMR 4198 under a 175 grain bullet, or I can try the Cream Of Wheat method with some fast pistol powder and no bullet.. Any thoughts on pros or cons?

Thanks to all for all the helpful ideas, suggestions, and insight.

[brian1]

This picture is where I started:
207688
Looong neck 30-06 after pushing back the shoulder, before any neck trimming, formed without annealing, next to 7x57mm Mauser case

[vzerone]

You done very well Brian. That distance or gap you asked about is just enough that if the brass grows from firing and resizing that it's not up against the end of the chamber. It's a safety thing so you don't ram the case mouth into the ledge and kind of crimping which won't let the bullet release easy and raise pressure much. You probably wouldn't experience that with the Rolling Block as it doesn't have much, if any, camming power, but a bolt action sure does!!

You're getting closer to shooting!!!!! Enjoy

[marlinman93]

Since your cases really don't need a lot of forming, I'd load them at whatever load you hope to use and simply shoot them. No need to do a light charge, or use filler to fire form them. I've built cases that had a lot more brass movement during fire forming and gotten great accuracy shooting targets while fire forming.

[Texas by God]

The gun, man. The gun. Quit teasing us with brass pics. Dang I'm a nag.

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[brian1]

The gun, man. The gun. Quit teasing us with brass pics. Dang I'm a nag.


Oh, the GUN ;-) It's night now, so hard to get any decent pictures, but I'll take some tomorrow

[brian1]

Here are the pictures of it.
207790

207791

Hmmm. What I uploaded was quite a bit larger. If you click on these, you get a larger version, but still not a large as what I uploaded.

[brian1]

207793
207794

[vzerone]

Not bad at all Brian, nice rifle! Have fun with and we better hear about how it shoots.

[TCLouis]

Anneal them before you fire them.

[marlinman93]

Wonder if those punch marks on the stock were "kill counts"???

[Reverend Al]

Wonder if those punch marks on the stock were "kill counts"???

I was just thinking that myself ...

[vzerone]

Maybe deer kills?

[marlinman93]

Maybe deer kills?

That's what I was thinking too.

[kootne]

There is some interesting information in the Oct. 1959 American Rifleman on this subject of headspace in military rolling block rifles. James M. Twiggs quotes James R. Lewis Jr. (then a patent attorney for Remington). In reference to the 7mm rifles, James Lewis says "almost without exception they are within the limits of the manufacturing gauges but this does not mean they are within the headspace tolerances of modern ammunition." He also notes the SAAMI standards for the 7x57 were not established until about 1920. In addition, he says the headspace compared to modern standards is "grossly excessive". However, in his experience, firing them with modern ammo didn't cause separations but all cases showed the bright ring characteristic of incipient head separations and could not recommend firing them "unless their use is limited to strictly fresh ammunition of characteristics consistent with the period of their original design and manufacture".
As an additional bit of information about the 7mm ammo, I have a couple Mauser clips of 7mm ammo dated 96 that I found in some of the effects of my great grandfather who was a veteran of the war with Spain, serving in the Puerto Rico campaign. The shoulder on this ammo is visually further forward than current ammo I compared it to. Makes me curious about whether this is an issue in 7mm military mausers. Also, rifles and ammo manufactured for military use probably don't have reloadability of fired cases very high on the priority list.

[Texas by God]

That's a great looking rifle.

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[brian1]

Maybe deer kills?

That's my guess, as I see no evidence anywhere on the rifle that it was military.

[brian1]

Well, after getting all my brass cut down and annealed, I formed a couple and trimmed them to 2.255". I loaded one up with a 175 gn RN Hornady over 20 gn IMR 4198. My Speer loading book from 1979 was the only one that mentioned a reduced load for old guns. They said 22.0-26.0 of 4198 for the reduced load, and said that should give me 1633-1915 fps. I initially seated the long bullet WAY out, like only about 1/3 down the neck, just to see if it would touch the lands when I chambered it. It did not. I decided to think about bullet jump distance later, and seated it to just short of the cannelure, which was about 80-90% of the way down the neck.

I fired it this morning. The chrony said 1336. All seemed fine, but when I ejected the case, I was surprised that one side of it was all blackened. I've never seen this before, so I really don't know what it means. It certainly appears that gases were going back, but not all the way to the head. It also didn't blow the case out much, as I can still see impressed in the neck how far the bullet was seated. I could add a couple grains of powder, to bring it up to the starting load; I just wanted my first shot to be very conservative.

Before I go any further with this, I'd like to hear your opinions on my observations, especially the blackening. The fact that the charge didn't even fully blow out the neck may be because I started a bit under the starting load. But I don't want to add more powder until I know what's up with the blackening and if it's safe to continue. These cases were all tumbled overnight, and were all shiny and like new before I fired.

Clean side of brass:
208054

Closeup of neck:
208055

Blackened side of case:
208056

Closeup of blackened side of neck:
208057
It's pretty clear how far down the bullet was seated, and it didn't expand the neck at all, other than where the bullet expanded it.

I annealed before forming; should I have also annealed again after forming?

[marlinman93]

It means one of two things (or both). It is usually a sign of too little pressure and the case isn't sealing in the chamber. It can also be caused by brass that's too hard and might need annealing. I'd up the charge first, as 1336 fps is pretty low for the bottleneck 7x57 cartridge.
Might consider a little faster burning powder also to bump the pressure up.

[Nueces]

That's my guess, as I see no evidence anywhere on the rifle that it was military.

It's possible that it was used during the long period of 20th century revolution in Mexico.

[Texas by God]

The brass did not seal against the chamber wall. More powder is needed badly.

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[brian1]

Well, I loaded up a couple more. One with 22 grains of IMR 4198, one with 22 grains of AA 5744. My chrony didn't record the first shot with 4198. It opened up the neck more fully than the last time, but not completely, and there was only a small amount of blackening on the neck. On the second shot, with 5744, I recorded 1650 fps, less blackening than the 4198, and it fully opened up the neck. Maybe another 0.5-1.0 grains.

I am having a hard time understanding the whole low pressure loading thing. We use reduced loads to keep pressures low for old guns. But it appears to me that the reduced loads are done with faster powders, like 4198 and 5744. This doesn't make sense to me. I would think we'd be using much slower powders for reduced loads, not faster ones. All the more so with the long barrels in rifles like the Rem RB. It seems to me that a fast powder is going to produce much more of a shorter, higher pressure spike, that may not even last until the bullet is out of the barrel, than a slow powder that starts off slow, without a quick pressure spike, then continues burning and maintaining pressure as the volume (bullet going down barrel) increases. I suppose there must be some fallacy in this logic, as all the reduced loads I've seen recommended call for small amounts of faster powder, but I just don't see where the error in thinking is.

Here's a simple graph I made of what I'm talking about; blue is a fast powder, red is a slow powder. Wouldn't it happen like this, and if so why wouldn't we be better off with slow powders when we want to reduce pressure, especially in a long barrel?
208247

[marlinman93]

I wouldn't consider either of those powders as "fast". And if I wanted to shoot reduced loads, I'd look to other powders that truly are fast burning and will generate a quicker rise to the same pressures. Then you could likely have a good seal and even do so at lower velocities.
Powders like Unique, Red Dot, Green Dot, etc. will all seal the case/chamber well and at lower velocities. A load of 12.0 grs. Unique will give around 1500 fps with a 148 gr. bullet and seal great. You might end up 1.0 gr. higher with your heavier bullet.

[brian1]

Perhaps I should have mentioned that I am shooting jacketed bullets in this (cuz I have a bunch of 175gn and 145 gn jacketed and no cast ones), so I am trying to limit PRESSURE due to the perceived limitations of the action steel,and I'm only looking at velocity as an admittedly poor gauge of what's happening inside when I fire it. I'm not really trying to limit velocity. For me, it can have all the velocity it wants, as long as pressure stays low. So that's why I think I want to seek a slower rise to a given pressure, rather than a fast rise. Is this thinking wrong?

[vzerone]

They don't use slow powders in reduce loads because they need to be a more full load so the powder burns more efficienty. Take for example you can't reduce recommended loads of WW 296 by much at all. I know that's a pistol powder, but one you don't reduce the recommended loads. You can run into a SEE problem.

Top loads I'm seeing for the 4198 powder, which are reduced velocity, is in around 26 grains. It's not a choice powder for standard 7x57 loads. What other powders do you have.

[brian1]

Oh, lots of choices; H CLAYS, Bullseye, Titegroup, SR7625, HP-38, SR4756, 2400, VV N110 (lots), IMR4227, AA5744 (lots), Norma200, IMR4198, H4198, H322, IMR3031, VV N133 (lots), IMR4895, IMR4064, Varget (lots), IMR4320, IMR4350, IMR4831, H50BMG (lots), VV 20N29 (lots)

I was using the 4198 because the only reduced load I could find for 7mm was in my 1979 Hornady book, and it said to use 4198 for reduced loads. Current Hornady book doesn't even mention reduced loads. I also tried 5744 because I have a lot of it and I've heard it's good for reduced loads. I use the 5744 in my muzzleloader ;-)

[vzerone]

Oh, lots of choices; H CLAYS, Bullseye, Titegroup, SR7625, HP-38, SR4756, 2400, VV N110 (lots), IMR4227, AA5744 (lots), Norma200, IMR4198, H4198, H322, IMR3031, VV N133 (lots), IMR4895, IMR4064, Varget (lots), IMR4320, IMR4350, IMR4831, H50BMG (lots), VV 20N29 (lots)

I was using the 4198 because the only reduced load I could find for 7mm was in my 1979 Hornady book, and it said to use 4198 for reduced loads. Current Hornady book doesn't even mention reduced loads. I also tried 5744 because I have a lot of it and I've heard it's good for reduced loads. I use the 5744 in my muzzleloader ;-)

Brian, you could just about use all those powders you listed. What velocity you wanting to shoot? You know that rifle will shoot factory loads. We're not talking about trying to make a 7mm Mag out of it. You can load it up some. Get in your manual and look at data for some of the powders you listed and just load the beginning loads which most often are very mild loads.

[brian1]

Oh. I was under the impression I had to use reduced loads because the gun would be damaged by factory loads. I'm really not too concerned about velocity; just pressure. Whatever velocity I get with a load that doesn't harm the gun is fine with me. I'll try a load in the middle of the pack of choices; maybe IMR 4831 or 4350. Thanks for the tips!

[vzerone]

Oh. I was under the impression I had to use reduced loads because the gun would be damaged by factory loads. I'm really not too concerned about velocity; just pressure. Whatever velocity I get with a load that doesn't harm the gun is fine with me. I'll try a load in the middle of the pack of choices; maybe IMR 4831 or 4350. Thanks for the tips!

Yeah American factory loads are loaded low, although there may be some newer stuff out there that is hotter. You'll be okay with starter load and mid loads for sure. You know too those old 7x57 have generous bores and grooves.

[marlinman93]

Oh. I was under the impression I had to use reduced loads because the gun would be damaged by factory loads. I'm really not too concerned about velocity; just pressure. Whatever velocity I get with a load that doesn't harm the gun is fine with me. I'll try a load in the middle of the pack of choices; maybe IMR 4831 or 4350. Thanks for the tips!

Out of about 150 powders on the burn rate chart 4350 and 4831 are #118 and #123, so not fast powders or middle of the pack either. 4227, H4198, or 2400 would be more "middle of the pack" powders. 2400 has been many shooter's choice for decades for lighter loads. I've used it for decades in reduced loads with good accuracy, and no sealing issues.

[Reverend Al]

The bottom cartridge is a 7x57 loaded for my South American Roller and you can see that the 175 grain semi-spitzer is loaded as far out of the case as is possible with the neck still holding onto it enough so that it won't fall out! (And the bullet is still well off the throat in my rifle ...)

https://i.imgur.com/Qr1vfPo.jpg

[brian1]

Interesting. Mine may end up seated way out like that, after I get done setting a load. I did an initial test with mine seated, not quite that far out, and it still wasn't touching the lands. It shoots OK Like that?
What's the top round - 300 BLK?

[brian1]

2400 has been many shooter's choice for decades for lighter loads. I've used it for decades in reduced loads with good accuracy, and no sealing issues.

What sort of starting load in 2400 would you recommend for this 7x57mm? I can't find 2400 listed in anybody's book for 7x57.
thanks,
brian

[vzerone]

Brian why don't you stop beating yourself to death over loads and shoot the beginning to medium loads in the books for jacketed 175 grain bullets? The 4898, 4064, 4320, 4350. I think you will be pleasantly surprised.

[brian1]

Yeah, that's what I did earlier today, using 2 of the powders listed in several of my books.
5744 23 gn 1796 fps
4198 24 gn 1662 fps
4350 37 gn 2011 fps
4831 37 gn 1738 fps
The 4350 seemed to be the best result on the brass. Lee manual said to use 37-40 grains. Most of Lee's recommendations are well below others'. Sometimes their "max" load is below others' starting loads. My 1979 Speer book said 44-48 grains, 2015 Nosler book said 43-47, 2016 Hornady book said 35-43. So I went with 37. Now I'll load up several with 4350 and see what the gun likes for accuracy.

[vzerone]

Yeah, that's what I did earlier today, using 2 of the powders listed in several of my books.
5744 23 gn 1796 fps
4198 24 gn 1662 fps
4350 37 gn 2011 fps
4831 37 gn 1738 fps
The 4350 seemed to be the best result on the brass. Lee manual said to use 37-40 grains. Most of Lee's recommendations are well below others'. Sometimes their "max" load is below others' starting loads. My 1979 Speer book said 44-48 grains, 2015 Nosler book said 43-47, 2016 Hornady book said 35-43. So I went with 37. Now I'll load up several with 4350 and see what the gun likes for accuracy.

That 4350 had the pressure up higher so the brass formed out like you said. I think the LEE loads would suit you. Those should be easy on that rifle. My old Speer manual says 41-45 grains.

[Reverend Al]

Interesting. Mine may end up seated way out like that, after I get done setting a load. I did an initial test with mine seated, not quite that far out, and it still wasn't touching the lands. It shoots OK Like that?
What's the top round - 300 BLK?

Yes, it actually shoots very well considering that the bore is fairly well worn and the lands are well rounded off on the edges. I shoot either 34.0 grains of IMR3031 or the same of IMR4064 with the 175 grain semi-spitzer bullets seated out at that length and it is typically keeping 5 shots under 3" at 100 yards, and usually with 4 of those in about a 2" group. I always seem to pull at least one wide flyer. (And that is with my fuzzy old eyes and the original open iron sights!)

[Reverend Al]

And yes, the top round is .300 AAC Blackout with a 220 grain round nose bullet seated out for my Remington 700 Blackout carbine.

[atr]

Nice thread,,,
I have a 7x57 model #5 and I have been shooting both cast and jacket successfully for many years. I agree that re-sizing and fire forming GI brass is the better way to go. The black smudge marks on the case you show is most likely a result of the brass not expanding enough to seal the chamber..i.e. a load that is to weak. I always check the cases to make sure that the breach block rolls up tight against the chamber. I have on occasion found that escaping gas will flow back through the firing-pin hole in the breach block so WEAR safety glasses.
I have loaded my 7x57 to 80% of maximum (J's) with no problems. When using cast I tend toward the upper end so that I am assured that the brass will expand enough to seal that chamber.
You rifle looks to be in very good condition. Good luck and good shooting
atr

[EDG]

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

All that headspace is probably caused by a too deep chamber.

[brian1]

All that headspace is probably caused by a too deep chamber.

Yes, I think that's what it is. The breechblock still closes fully with the oversize cases, so its angle against the case & barrel should remain the same 90 degrees. I'll keep an eye out for angled heads, though. I haven't done any more on this lately - been busy - but I hope to load up a handful and try them before going ahead and process the whole batch of 50+.
Thanks to all for their advice on this.
brian

[EDG]

A friend of mine had one with a longer shoulder and shorter neck. His first shot pierced the primer. The escaping gas blew the hammer back and the action opened. The primer pocket was blown and the primer was stuck on the end of the firing pin.
The case stayed in the chamber and he was not injured. He expanded his 7x57 brass and formed a new shoulder to fit the chamber and the gun worked fine.