7.63 Mauser Load Data

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AdmKeth
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7.63 Mauser Load Data

Post by AdmKeth »

Hi everyone,

I have been a long time lurker and this is my first post, so be gentle :)

This post is going to be long, but entertaining, so grab a pint and sit back…

A bit of background before I present my question.

I have been responsibly using firearms since I was a wee lad, about 47 years ago. My dad (God rest his wonderful soul) was with the 90th Infantry “Tough ‘Ombres” Division at Utah Beach on D-Day, so collecting and using firearms is in my family blood. I have fired everything from .22 Derringers, 1911 .45 ACPs, 22-250s, .357s, .44s, side-by-side coach guns, Thompson Commandos, M1 Garands and more. In my youth I have hunted (mostly ground squirrels at a cattle ranch), shot trap and skeet, and a boatload of paper targets. I now own a Taurus PT-908, Browning pump 12-gauge, and a Winchester .30-.30. My prides and joys, though, are a couple of pieces my dad picked up while he was over in France during the war.

During one of the actions that he received one of his three Purple Hearts (two with Oak Leaves…I’m lucky to be here!) he acquired a beautiful 7.63 Broomhandle Mauser with the wooden holster/stock. Later on, he horse-traded some other captured items for a Red 9 Broomhandle. Both he brought home as war prizes (I still have the official US Army paperwork for the 7.63), and he acquired a wooden stock/holster for the 9mm shortly after his return from his European vacation (which it was anything but…only man I know that has been shot at by the same King Tiger twice and lived (barely) to tell about it, but that’s another long story).

Dad passed away back in 2009 (pours a libation of Wild Turkey), but before he did, he bequeathed to me the two beautiful Mausers, several stripper clips and a small supply of ammunition. Until recently, I kept them in secure storage, not giving them much thought. Recent world events have caused me to consider them again, and I thought I should at least take them to a reputable gunsmith and have them inspected to ensure they we safe for light use. I toddled down to a gunsmith my dad had used, lo so many years ago, and had them thoroughly disassemble, clean, oil and certify both pistols safe for firing. The gunsmith reported that despite some very light barrel pitting, both weapons could be used.

Having received a clean bill of health for my treasures, I figured I would need some ammunition more recent than the 200 rounds of 7.63 from the 1950s. One of the name brands on the old boxes was Fiocchi, and I was pleasantly surprised to discover that they still produced occasional batches of 7.63, but to my dismay, importing to the highly restrictive state in which I live means the gunsmith adding a substantial surcharge to a previously inexpensive box of ammunition…and it gets worse in July of 2019. So, effectively, the state in which I live has forced me to load my own.

I have been responsibly owning and using firearms for pretty much my entire 60 years. Never have I had to “show my papers” to purchase ammo. Thus, I have made the decision to reload my own, as buying brass, bullets, powder, and primers is still (so far) pretty easy. One of my fondest memories from when I was a teenager was that during summer break from school, dad would have us kids sit at the workbench and reload hundreds of .45, 22-250, .357, and 12-gauge rounds for our hunting and camping excursions. Thus, I am no slouch when it comes to reloading, just a little rusty.

I have done a TON of reading, especially on these forums (thank you prior posters!). I recently invested in a Lee Precision Turret Press, 30-caliber pistol Mauser dies, 9mm dies, and lots of essential accessories, such as a digital powder scale, trickler, lube pad, and more. I picked up 500 rounds of Starline 7.63 Mauser brass, Sierra 85 grain FMJ bullets, Unique powder and Winchester SPP. I have both the Lee reloading book, and the Lyman 50th reloading book. I have read everything I can find, both in books, internet, and the information which accompanied the dies on the range of loads for the 7.63 Mauser (I’ll get to 9mm loads in another post). I have compiled all of my findings in a spreadsheet.

So, finally, this brings me to the point of the post…

Before I seat even one bullet, I wanted to verify and validate my assumptions and findings with someone else to ensure I wasn’t going off half-cocked (pun intended).

Lastly, local gun stores where I can go and pick people’s brains have all but disappeared. One where dad use to shop, in particular, after having been at their location for over 60 years, closed their doors.

First, foremost, and always, I want to ensure safety. I want whatever load I put in these pistols to not blow up a priceless piece of personal family history, and reliably cycle the action without any FTEs or breaking the bolt stop.

Again, just to recap, I am using the following:

Starline 7.63 Mauser brass from Graf & Sons (#SU30MSR)
Sierra 85 gr .308 RN bullets from Graf & Sons (#SRA8005)
Unique powder (local reloading store)
Winchester SPP

After lots and lots and lots and lots of reading, comparing loads, bullet weights, and powder types, I have reached the following loads, and I hope folks will double check my math and tell me if I am wrong. Reminder, I am leaning towards starting out with light loads with the expectation of FTE and manual cycling of the action, but please correct me. I intend to load two rounds of each of these and perform tests at a local outdoor range.

I will start with 5.2 grains (1003 fps), then…
5.4 grains (1026 fps)
5.6 grains (1049 fps)
5.8 grains (1072 fps)
6.0 grains (1095 fps)

According to what I have read, I have a Do No Exceed of 6.8 grains (1187 fps), but I am not sure there is even enough room in the cartridge for that much, so I am going to stop at 6.0, for safety’s sake.
I genuinely appreciate any feedback. Once I hear back from folks, seat a few bullets, and conduct my field tests, I’ll report back here with the results.
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Re: 7.63 Mauser Load Data

Post by RBHarter »

So that's what it looks like when I explain everything !

Neat story and a great possession .

I recently went rounds chasing data for 7.62×25 Tok the high pressure sister . Your numbers look like what I had in mind for the cast loads .
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Re: 7.63 Mauser Load Data

Post by Ranch Dog »

Welcome to the forum, and God Bless your dad! I enjoyed the background material!

The only thing I can add to your load considerations is to make sure you use the overall length from the data you are using as a minimum. Any shorter of a cartridge OAL will increase chamber pressures. With that in mind, I start with a dummy cartridge to make sure that it will chamber. Keep us posted and we are going to need some pictures!
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Re: 7.63 Mauser Load Data

Post by AdmKeth »

Thanks for the warm welcome and the responses.
Ranch Dog wrote: Welcome to the forum, and God Bless your dad! I enjoyed the background material!
Thank you, kind sir. Dad was the kind of guy that every son should have. He loved camping, motorcycles, firearms, and trains. He taught all four of his sons to ride, drink, and shoot responsibly, and I exercise those values to this day. I honor his memory each Veteran's Day and Memorial Day by pouring a libation of either Ancient Age or Wild Turkey.
Ranch Dog wrote: The only thing I can add to your load considerations is to make sure you use the overall length from the data you are using as a minimum. Any shorter of a cartridge OAL will increase chamber pressures. With that in mind, I start with a dummy cartridge to make sure that it will chamber.
Aye, I have been noting the cartridge overall length as minimum ~ 1.325 and maximum ~ 1.36. Alas, I was just starting to dial in the seating dies when the battery died in my calipers as I was seating a couple of dummy cartridges, so I am not going to put primer and powder to case until the new packages of batteries arrive and I lock in the dies </waits at door for Amazon delivery dude>.
Ranch Dog wrote: Keep us posted and we are going to need some pictures!
I'll take a group photo of both pistols/stocks on Saturday with some close-ups of the 7.63 for this thread and post them Saturday afternoon. I'll post close-ups of the Red 9 when I post my questions/assumptions in a separate thread next week (still researching and verifying some data).
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Re: 7.63 Mauser Load Data

Post by Macd »

Thanks for sharing and a hearty welcome from Newfoundland.

Just a few points that you may wish to note. You may already know these but others read the forums who may find them useful

- The 7.63 Mauser, (.30 Mauser)(not to be confused with the .30 Luger) is a bottle necked case that head spaces on the shoulder. When FL sized it should chamber in any pistol with a chamber that is within spec. Once fired, brass life and performance can be improved by sizing just enough to allow the action to fully close and to operate reliably. The amount of sizing that is required will vary from pistol to pistol.
- The bullet you are using apparently doesn't have a crimp groove. When setting seating depth the longest COL that fits the magazine, loads and cycles reliably may provide the best accuracy. Regardless I suggest a good tapered crimp or the use of a FCD from Lee if available. A semi's recoil may cause bullets to set back if they do not have enough neck tension.
- The nominal bullet size and groove diameter per CIP spec is .309 (~7.86mm). Like all military surplus firearms the actual barrel dimensions may be larger and a .310 -.312 bullet may be more suitable. The only way to tell for sure is by slugging the barrel. There are some good .32 calibre bullets available in both cast and jacketed.
- The 7.63 is a high pressure round (CIP Pmax is 2250 Bar (32,663 psi)). My cartridges of the world (Edition 8) lists 5.2 grains of Bullseye under an 86 grain bullet as providing close to factory performance at 1,410 fps. I would start at least 1/2 a grain below that and work up.
- do not use 7.62x.25 Tokarev which is very similar as this round has a higher Pmax at 2500 Bar (36,259 psi).

I have always wanted a C96 having fired one that a friend inherited from his great uncle along with a Swiss Luger in 7.65x21 (.30 Luger). If I recall correctly we were shooting PRVI (PPU) 85 grain fmj rounds in the C96 and they really snapped.
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Re: 7.63 Mauser Load Data

Post by AdmKeth »

Macd wrote: Thanks for sharing and a hearty welcome from Newfoundland.
</tips hat> Howdy, sir.
Macd wrote: Just a few points that you may wish to note. You may already know these but others read the forums who may find them useful
I am a Technical Writer by trade, so I am always open to helpful advice and constructive criticism. I pride myself on not knowing everything, but being open to learning.
Macd wrote: - The 7.63 Mauser, (.30 Mauser)(not to be confused with the .30 Luger) is a bottle necked case that head spaces on the shoulder. When FL sized it should chamber in any pistol with a chamber that is within spec. Once fired, brass life and performance can be improved by sizing just enough to allow the action to fully close and to operate reliably. The amount of sizing that is required will vary from pistol to pistol.
Got it...thank you.
Macd wrote: - The bullet you are using apparently doesn't have a crimp groove. When setting seating depth the longest COL that fits the magazine, loads and cycles reliably may provide the best accuracy. Regardless I suggest a good tapered crimp or the use of a FCD from Lee if available. A semi's recoil may cause bullets to set back if they do not have enough neck tension.
Excellent advice, thank you. Investigating and investing.
Macd wrote: - The nominal bullet size and groove diameter per CIP spec is .309 (~7.86mm). Like all military surplus firearms the actual barrel dimensions may be larger and a .310 -.312 bullet may be more suitable. The only way to tell for sure is by slugging the barrel. There are some good .32 calibre bullets available in both cast and jacketed.
This is the kind of excellent technical information for which I was hoping to receive here. Thank you.
Macd wrote: - The 7.63 is a high pressure round (CIP Pmax is 2250 Bar (32,663 psi)). My cartridges of the world (Edition 8) lists 5.2 grains of Bullseye under an 86 grain bullet as providing close to factory performance at 1,410 fps. I would start at least 1/2 a grain below that and work up.
</scratches head>1400 fps seems like a wee bit more power than I might be comfortable with. I was intending to stay in the 1100 fps range to limit wear on the bolt stop. I just need it to cycle the action and eject the case, not stop a T-34. Am I being too cautious?
Macd wrote: - do not use 7.62x.25 Tokarev which is very similar as this round has a higher Pmax at 2500 Bar (36,259 psi).
Already aware of that caveat and the reasons why. Thank you.
Macd wrote: I have always wanted a C96 having fired one that a friend inherited from his great uncle along with a Swiss Luger in 7.65x21 (.30 Luger). If I recall correctly we were shooting PRVI (PPU) 85 grain fmj rounds in the C96 and they really snapped.
Verily. The C96 is a unique, readily recognizable, respected, and highly sought after piece of history. I intend to care for mine until I am willing to bequeath them to my nephew.

Macd, thank you for your advice. </salute>
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Re: 7.63 Mauser Load Data

Post by AdmKeth »

Macd wrote: - The bullet you are using apparently doesn't have a crimp groove. When setting seating depth the longest COL that fits the magazine, loads and cycles reliably may provide the best accuracy. Regardless I suggest a good tapered crimp or the use of a FCD from Lee if available. A semi's recoil may cause bullets to set back if they do not have enough neck tension.
Taking your advice to heart, I hied myself home and consulted the colorful insert which came with the Lee Precison 30 Mauser dies. Much to my delight, it listed a bottleneck crimping die 90086. Furthering my fortune, Amazon listed one for $19. It will be at my doorstep by Saturday :D

Again, thank you.
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Re: 7.63 Mauser Load Data

Post by Macd »

Your comment on 1410 FPS prompted me to phone my friend to get his take. He collects military surplus handguns. He agreed with your concern and of course my caution to start 10% below the published load. He replaced the springs in his pistol with a new set from Wolf. Apparently the originals weaken over time allowing the hotter loads to batter the slide stop. He wasn't sure without checking his records but he believes the PRVI rounds were over 1400 FPS. If you like I can run some Quickload calculations and see what powder charges will keep you around 1100 FPS.

Edit: He checked. His records show an average of 1493 FPS. PRVI specs the muzzle velocity at 1510. The Wolf springs options are here. https://www.gunsprings.com/MAUSER/1896- ... D40/dID172
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Re: 7.63 Mauser Load Data

Post by AdmKeth »

Macd wrote: Edit: He checked. His records show an average of 1493 FPS. PRVI specs the muzzle velocity at 1510. The Wolf springs options are here. https://www.gunsprings.com/MAUSER/1896- ... D40/dID172
Brilliant! The prices are quite reasonable, too!

Follow-up question to the round itself and reloading brass:

I expect that even after the first firing (and chasing brass) of a round that I am going to need to gauge and possibly trim the case. Of course, Lee doesn't make a dedicated 7.63x25 case length gauge...will the 7.62x25 Tokarev Case Length Gauge work as a stand-in? If not, what are my options?
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Re: 7.63 Mauser Load Data

Post by RBHarter »

Many use the chamber as a gauge for a plunk test . Basically drop a round in the chamber if it goes all the way down it's good to go ..... probably not really useful for a Luger . It should be noted that cartridges that fit a gauge will likely be well under sized in your pistol as most gauges are made to a minimum tolerance . If your example is say a first cut chamber war production from say late 1918 or mid 1943 on to June of 45' the chamber may be huge . Saving tooling often leads to a reamer being started as much as .001 over maximum design size and with a bottle neck letting it hit the shoulder short to make up for the fat . So fired cases might look like an improved cartridge . They were also , late in the wars , used down to one hone under minimum . So the fired brass might all but go in a standard size gauge especially if you happen to get a first cut gauge with a last cut chamber .

My system for autos has kept me out of trouble .
I load 5 rounds per step in reasonable steps per the load window .
I try to do at least 5 steps but prefer 7-10 .
I shoot every load for group .
I stop and make notes when I get full cycle and lock open . I consider this a minimum load for that gun . Now at that point often the groups are what is expected for the gun .
If there is a clear trend in the groups closing for example I will go on up .
5 rounds is ideal here because if a magazine fed pistol is going to have feed issues it will be the last 3 rounds from the mag .
I have had 1 pistol that was continuing to close at a maximum load . Mostly all of the others were at their best 1 or 2 steps above above clean cycle .
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