Loading for 30 Luger 6 in barrel - early days - testing powders

[Kiwi]

Much excitement with the arrival of my Interarms Mauser Parabellum in .30 Luger. Of course the first step was to field strip and examine. The 'used' gun was bone dry and showed no signs of being fired, certainly not in many years if at all. A good oiling and reassembly and it was ready for the range.

Ignorance is not always bliss, I ripped a bit from my thumb loading the magazine not knowing to use the loading tool. Thumbs bleed profusely.
While waiting for my paperwork to clear I had purchased some Prvi Partizan, and RCBS dies (auction $30).
I started with the Prvi, The toggle would not snap closed, but with one in the breech then the magazine inserted it cycled fine, 1 jam in the first 15 rounds. I should clarify that as a bullseye shooter I am used to loading 5. Home, clean, inspect, re-oil.

I spend a couple of days reading the reloading section of this site, found 85gr projectiles at Graff (got a few hundred) and started calculating powder loads, from posted loads, powder burn speed charts, and my reloading booklets from Hercules and IMR, I ignored Winchester as the only powder I have is WST a fast powder and the posts here indicate the Luger prefers a medium to slow powder which makes sense given my Mauser has a .30 bore and 6 inch barrel. Thinking here was narrow barrel like a rifle compared to fat barrel like a 12ga.

I have
Alliant Unique initially for 20ga but availability and low price has me buying rather than reload, this powder has been repurposed to 45 Colt where the economics of reloading really pay.

Alliant Herco initially came with a 12ga press and was not used until tried out with .45acp and is now my favorite powder for that.

IMR SR 7625 I was given a tin and use it for .380 reloads where it performs well.

I decided to make test loads of each and see if the gun cycles. From reading here I wanted to avoid the Unique if possible given the descriptions of dirty, but if it works, it works.

First problem was the decapping and sizing die would not bell the case. Where it should bell a teensy bit it just started to compress the shoulder. With no belling, bullet seating was careful but successful.

I load 8 rounds, just like Noah two by two
4.8gr. Herco I thought this was much too light and expect an FTE
5.8 gr Herco generally uses a slightly higher charge than Unique with slightly lower pressure

5.1 gr Unique I used Hugh's sticky – 5gr did not cycle a 93gr, and 6gr working in a shorter (3-7/8) barrel did work for an 85gr.

4.2 gr SR 7625 - for this I compared the 2 Alliant powders with this for relative loads and pressures on a 9mm 115gr to come up with the powder weight

All these were at the light end and intended as starter loads purely to see if the gun would cycle

And back to the range where I load 2 magazines with 4 each and fire all printing a nice 5 shot cluster in 1.75 inches, the other 3 not too far away and more due to me getting used to the trigger than anything else. The only surprise was the light Herco cycling.
The toggle does now snap closed with a mag in so the earlier problem was probably due to no oil and no use.

Next I will retest the Herco at 4.8 with a fuller magazine, and the SR 7625 with a lighter load and fuller magazine.

Haven't had this much fun since kindergarten

[rhuff]

Congrats on your "new" Interarms Mauser. I own one in 9mm, and really enjoy it. Also, welcome to the world of loading 30 Luger brass. It can be a challenge to find the right bullet, powder type, neck tension, and loading to make your Luger happy. Many of us on this forum load and shoot the 30 Luger cartridge.....some of us own other handguns in this caliber also.

I tried the fast powders initially, and got decent results, but not a 100% reliable end result, in my way of thinking. I am one of those folks that have been happy with using Unique powder in my 93gr bullet loads. I don't load many 85gr bullets anymore. I find that a full load of Unique, which is what is needed for my handguns to cycle reliably, is not a dirty load. The new Unique powder(formula) is a bit cleaner than the old stuff that I started with decades ago.

Basically one finds what one's Luger likes, and stick with it......and enjoy the ride in finding it!!

[idler]

I use 5 g. unique 93 g. cast bullet fires and functions fine in @ 1920s lugers and a 06/24 swiss 4-3/4 " bbl.

[K.Wilhelm]

Shooting .30 Lugers is way too much fun. Handloading for them is an adventure. I use GT's 93 grain swiss bullets with a medium load of HP-38 powder with really good results in both functionality & accuracy.

[Kiwi]

Part II.
Forgot to mention in prior post my appreciation for Sieger's post on O.A.L. I measured the Previ cartridges at 1.146 a little shorter than Spec 1.175. I loaded mine to as close to Spec as I could measure with my vernier 1.172.


Off to the range with 5 rounds loaded with Herco 4.8 to see if it cycles, and a two sets of 3 SR7625 loads going down from the successful 4.2 of last week.

Results:-
The Herco produced a 1.5 by 0.5 group with holes overlapping.
The SR7625 loaded with 4.0 did not feed well and did not group well
With 3.8 did not feed well and also had a FTE

Takeaways – more Herco to come and will try 5.0 as 4.8 is very light compared to factory.
Will try the SR7625 at 4.5 for accuracy.

So much fun

[Sieger]

Originally Posted by Kiwi

Part II.
Forgot to mention in prior post my appreciation for Sieger's post on O.A.L. I measured the Previ cartridges at 1.146 a little shorter than Spec 1.175. I loaded mine to as close to Spec as I could measure with my vernier 1.172.


Off to the range with 5 rounds loaded with Herco 4.8 to see if it cycles, and a two sets of 3 SR7625 loads going down from the successful 4.2 of last week.

Results:-
The Herco produced a 1.5 by 0.5 group with holes overlapping.
The SR7625 loaded with 4.0 did not feed well and did not group well
With 3.8 did not feed well and also had a FTE

Takeaways – more Herco to come and will try 5.0 as 4.8 is very light compared to factory.
Will try the SR7625 at 4.5 for accuracy.

So much fun

Kiwi,

It is good to see my practical advice being used as such. Thanks!

If I were you, I would stick with the Herco powder, as is seems to be in the perfect medium/slow burning range preferred by both 7.65 and 9mm Lugers.

Is the 4.8 grain load you listed the minimum load that will hold open your action upon firing? If so, with a full magazine of
8 rounds, latter up your test charges 1/10 of a grain at a time until you reach minimum group size, or, out run your springs (I'm guessing the range to be 4.8 to about 5.6 grains of Herco).

Hope this helps!!


Sieger

[Kiwi]

Sieger,

Thank you for your response

Not sure if the 4.8 is the minimum. I originally calculated 5.8, loaded them and they shot fine.
The 4.8 was a reading error on the scale. I was going to just unload using the bullet puller but decided to try them on the basis that the worst that would happen is a FTE or fail to cycle. I was surprised at how well they did. So Herco does work from 4.8 to 5.8 with good grouping.

The reasons to persist with SR 7625 is the burn rate is the same as Unique, I have a couple of tins of it and the only other cartridge I use if for is the .380 PPK/S which I do not shoot a lot of, so I would like to use it. Also the 7625 is a very fine powder that is consistent through a powder measure, most of the Hercules/Alliant powders are flakes with powder measure variations such that I throw low and top with a trickler.

Decision will ultimately be on group size and Herco is winning at this point