Nothing's More Rewarding than Handloading

Making 7.65 Mauser cases out of .30-06 brass requires a bit of work.Even after sawing off the .30-06's case neck, there's still plenty left to trim to the 7.65's final case length.

Reader Ira Polson recently requested load data for his favorite hunting rifle. That's typical of many inquiries I receive. Because that information is typically available in current reloading manuals, I rarely respond. Instead, I often remind readers to always use these reliable sources for safe, lab-tested recipes. But Polson's request was different. It involved a relatively obscure and, coincidentally, rather interesting rifle/cartridge/bullet combination. And it offered me the opportunity to get right down to what handloading is all about. It turned out to be a really rewarding exercise.

Polson's e-mail stated, "You're going to laugh when I tell you my favorite hunting rifle is an old 1891 Argentine Mauser. Dad bought it ($49.95) for me from Sears in 1955. I've used it for a long time to hunt deer and elk in Arizona and New Mexico. There's plenty of load data for 150-grain and heavier bullets. However, I'd like to shoot coyotes and javelinas. With AK and SKS carbines now all over the place, I can get 123/125-grain bullets to load in my 7.65 Mauser, but I can't find any load data. Can you help?"

The inquiry couldn't have come at a more opportune time.

Although I reload approximately 80 different cartridges, I'd never owned a rifle chambered in 7.65 Mauser until last fall. I purchased a "customized" 1891 Argentine rifle (i.e., military stock refinished, Pachmayr recoil pad instead of the original steel buttplate, and the bolt turned down). All the numbers matched, so I took a chance that it was safe and serviceable. Fortunately, after cleaning it several times, the bore also looked pretty good.

I purchased a box of Boxer-primed, 174-grain FMJ Prvi Partizan ammunition at my local gunshop and fired most of it. My aging eyes could almost get the front sight clearly focused and properly aligned with the 8-inch bullseye, and 50-yard groups were quite acceptable.

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I don't own a rifle or handgun that I don't reload for, and this latest acquisition wasn't going to be the exception. I picked up a set of RCBS dies and retrieved a box of Hornady 150-grain Spirepoints to reload my limited supply of once-fired brass. The Powley slide rule calculated a safe load, which I compared with Hornady's 7th edition load manual. With IMR-4320 or IMR-4064, 43.5 grains looked to be about right, so I assembled some test loads.

Unfortunately, this session occurred just a few hours before I read Mr. Polson's e-mail. I had considered loading Hornady's original (.311-inch), 123-grain bullets, but I also hadn't found any published data to validate the Powley calculations. Lyman's 49th edition handbook has recipes for Sierra's 125-grain Pro-Hunter bullet; however, it was developed in a 1909 Peruvian Mauser with the much stronger M98 action.

Now I had a legitimate reason to work up a few light-bullet loads for the 7.65 Mauser, but I was woefully short of brass. Then I remembered something I'd read in Sierra's manual. It stated that 7.65x53mm brass could be made by running .30-06 cases through the Mauser's full-length sizer die. I found a few odd pieces of once-fired commercial .30-06 brass and started experimenting.

The .30-06 case is nearly 2.5 inches long, while the 7.65 Mauser case is only 2.1 inches. Four-tenths of an inch is a lot to trim, even with a power tool. I concluded I could completely remove the parent case neck and still have enough material left to form a new neck and shoulder. I clamped a .30-06 case in rubber jaws on my bench vise and carefully sawed the neck off just above the shoulder. Next, I carefully faced off the rough saw cut using the RCBS power trimmer. I only removed a few thousandths of material and then deburred the inside and outside edges.

STEPS IN MAKING 7.65 MAUSER CASES: 7.65 Loaded Round, .30-06 Case, Case Neck Sawed Off, Rough Edges Trimmed, Case Neck Formed, Neck Expanded, Case Trimmed To Final Overall Length, 7.65mm Mauser With Bullet Seated.

After removing the decapper/ expander rod, I screwed the sizer die body into the press until it firmly touched the shellholder with the ram at its highest point, i.e., exactly the same setup I'd used earlier when resizing the once-fired factory cases. They had chambered snugly, which indicated the rifle's headspace was rather tight.

After lightly lubricating the now neckless .30-06 case, I carefully forced it into the die until the ram was fully extended. When I lowered the ram, the desired neck and shoulder were formed perfectly. The case neck was approximately 0.050 inch too long, and before I trimmed it, I re-installed the decapper/expander rod and ran the reformed case back through the sizer die to expand the neck to the proper diameter. After wiping the sizing lube off, I remounted it in the power trimmer, cut it to 2.090 inches, and again deburred the mouth inside and out.

Now came the real test. Would the newly formed case chamber in the rifle?

No. The bolt would not close.

I returned to the bench, screwed the sizer die in another quarter-turn so, hopefully, it would set the shoulder back a bit farther. After relubing the case sparingly, I ran it into the sizer die again. I wiped the lube off before trimming it and then tried once more to chamber it.

Success!
It was a snug fit just like my earlier handloads had exhibited, yet quite acceptable. I reworked the rest of the odd pieces and a box of once-fired military cases. Of course, I chambered each finished case, and they all fit just like the first one. I lost one case because I applied too much lube, which caused a dent to form in the shoulder.

The 7.65 Mauser's case capacity is actually about 5 percent greater than the .308 Winchester's, so one might assume it would be safe to use similar .308 recipes when loading the Mauser round. That would be a valid premise only if your handloads were to be fired in a modern rifle made from tough steel and heat-treated properly. This, of course, is not the case for surplus, century-old Argentine Mausers.

The .308's maximum average pressure limit is 62,000 psi. According to ST Ballistics Editor Allan Jones, Norma factory 7.65x53 ammo is loaded to the same pressures as the 7x57 Mauser (51,000 psi). However, we concluded that hand-loads for these old 1891 Mau

ser rifles should not exceed 44,000 psi. We centered on that figure because it is a generous 10-percent reduction from 51,000 psi and because working pressures for lever actions are in that neighborhood.

So what could I safely recommend to the reader? The Powley computer indicated that 45.0 grains of the propellants I'd loaded with heavier bullets would be okay, but how should I bound that value or was that charge weight actually near maximum?

Fortunately, Hodgdon's loading manual helped resolve my dilemma. The most recent edition provides both start and maximum charges with corresponding pressure data for IMR, Hodgdon, and Winchester propellants. Of course, it didn't include any 123- or 125-grain bullets for the 7.65 Mauser--or pressure data either--because this not-so-popular round hasn't been retested in the lab recently.

However, there was plenty of .308 Winchester load data for the 125-grain Sierra bullet. I reasoned that because the 7.65 Mauser's case capacity and bore volume was just a bit greater, I should be able to use the starting loads listed if the corresponding pressures shown did not exceed 44,000 psi. With this rationale as my guideline, I was able to develop some quite satisfactory handloads.

I had some early (.311-inch) and current production (.310-inch) 123-grain Hornady jacketed softpoints on hand, and I ordered a couple boxes of Sierra 125-grain Pro-Hunter Spitzers. ST Gunsmithing Editor Reid Coffield contributed some new Norma brass (that he hadn't needed for 20 years) to the cause. And I secured a couple boxes of Hornady Custom ammo to complement my limited but growing inventory of 7.65 munitions/components. The chart on page 20 shows the results I recorded while shooting 200+ rounds at the range.

I enjoyed developing a "practical" response to Mr. Polson's inquiry. Now he can enjoy shooting his favorite hunting rifle, and I hope he pops a 'yote for me

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7.65x53MM MAUSER LIGHT-BULLET LOADS
Bullet	*Powder (Type/ Grs.)	*Velocity (fps)	**Powder (Grs.)	**Velocity (fps)	Overall Length (in.)
Hornady 123-gr. JSP(.310)	N201 / --	--	45.0	2854	2.79
Hornady 123-gr. JSP(.310)	IMR-4895 / --	--	46.0	2876	2.79
Hornady 123-gr. JSP(.310)	IMR_8208 / 43.5	2732	--	--	2.79
Hornady 123-gr. JSP(.310)	BL-C / --	--	49.0	2947	2.79
Hornady 123-gr. JSP(.311)	BL-C / --	--	49.0	2947	2.82
Hornady 123-gr. JSP(.311)	N201 / 43.0	2727	45.0	2887	2.82
Hornady 123-gr. JSP(.311)	IMR-4895 / 44.0	2693	46.0	2929	2.82
Hornady 123-gr. JSP(.311)	H4895 / 42.0	2643	44.0	2820	2.82
Hornady 123-gr. JSP(.311)	IMR-4064 / 45.0	2746	46.5	2868	2.82
Hornady 123-gr. JSP(.311)	BL-C(2) / 47.0	2691	49.0	2843	2.82
Hornady 123-gr. JSP(.311)	IMR-4320 / 45.0	2682	47.0	2812	2.82
Hornady 123-gr. JSP(.311)	VV N540 / 45.0	2571	48.0	2820	2.82
Sierra 125-gr. PHS(.311)	N201 / 45.0	2809	46.0	2928	2.86
Sierra 125-gr. PHS(.311)	IMR-4895 / 45.0	2705	47.0	2902	2.86
Sierra 125-gr. PHS(.311)	IMR-4064 / 45.0	2672	47.5	2881	2.86
Sierra 125-gr. PHS(.311)	IMR-4320 / 45.0	2682	47.5	2859	2.86
Sierra 125-gr. PHS(.311)	H4895 / --	--	45.0	2829	2.86
Note: All load data should be used with caution. Always start with reduced loads first and make sure they are safe in each of your guns before proceeding to the high test loads listed. Since Shooting Times has no control over your choice of components, guns, or actual loadings, neither Shooting Times nor the various firearms and components manufacturers assume any responsibility for the use of this data.
*=Starting Loads, **=Max Loads