Hot-Rodding 7.65 Para

[Michael Zeleny]

I understand that 7.65 Para ammo takes about 1/7 more powder for the carbine than the pistol loads: 0.40g for the former and 0.35g for the latter, packed in DWM blackened cases topped with cupro nickel 93gr point bullets. Is there any reason a properly sprung W+F 06/29 pistol shouldn't be fed with this kind of ammo?

[Ron Wood]

The reason the carbine ammo was loaded hotter was to overcome the increased mass of the carbine barrel/receiver and cause the action to function properly. Don't know for sure, but since a W+F 06/29 does not have this increased mass it would seem that the hotter round would not be good for the action. Kind of like shooting hot submachine gun ammo in a Luger pounds the bejeebers out of the toggle train and eventually leads to cracks or worse, spontaneous disassembly. Plus, original carbine ammo is scarce and very, very expensive .

[Michael Zeleny]

Your analysis appears to assume the popular theory, that the toggle action is not nearly as sensitive to the chamber pressure, as it is to the recoil impulse. In other words, we ought to be able to improve ballistics with no wear penalty, by upgrading the springs and adding some ballast to the cannon. I understand the reasons for hot-rodding carbine ammo accordingly, and expect them to apply in spades to my 180mm factory heavy barreled W+F 06/29. I am trying to find a Swiss source for replicating this piece, but so far without luck. Generally speaking, my experience suggests that bottleneck 7.65 Para is much more reliable and a bit more accurate in a Luger, than its tapered straight-walled junior sibling. Hence my interest in upgrading its ballistics to a level appropriate for social work.

Incidentally, the W+F 06/29 was made long after 1918, but not as any kind of reproduction.

[nukem556]

I'd think with a good stiff new Wolf 9mm spring, you could load a bit hotter, certainly than Winchester or Fiocchi ammo, at least. Check out the latest addition of Lee's loading manual.....there are loads in there for a 93gr bullet using AA#7 breaking 1400fps that are within accepted pressure specs

[Sieger]

Mike:

I agree with Ron, but would add that the number one cause of Luger mechanical failure is when the rear of the toggle assembly strikes the rear of the frame. With properly loaded ammo, this does not happen. With hot stuff, it does.

Another thing to consider is the rate of twist of the barrel. This twist was not designed for fast ammo and will not shoot it accurately.

For "social work" I'd buy another design pistol in either .45 or .50 caliber, though the Swiss Army must have been convinced, for some 40 years, that the little 7.65 was adequate for "social work".

Sieger

[nukem556]

There's a can of worms...the old canard about "overstabilizing' a bullet...I dont think it can happen in the real world. Understabilzation with too slow a twist is very apparent....bullets keyholing and hitting a target (if at all) sideways. I've been a Service rifle shooter for years, mainly using a AR15 with one of Kreigers excellent barrels in a 1/7 twist. This is to stabilize the long 80gr bullet for the 600yd stages. For reduced 100-200 yard matches, I've shot zillions of 52gr bullets through the same barrel with knife-edge 1/2 MOA accuracy....mind you, a 52-55gr bullet only requires a 1/14 twist to stabilize, so they're spinning TWICE as fast as designed! The incremental increase of bullet rpm say from 1200 fps to 1400fps is negligible, as is the effect on accuracy.

[Sieger]

Originally Posted by nukem556

There's a can of worms...the old canard about "overstabilizing' a bullet...I dont think it can happen in the real world. Understabilzation with too slow a twist is very apparent....bullets keyholing and hitting a target (if at all) sideways. I've been a Service rifle shooter for years, mainly using a AR15 with one of Kreigers excellent barrels in a 1/7 twist. This is to stabilize the long 80gr bullet for the 600yd stages. For reduced 100-200 yard matches, I've shot zillions of 52gr bullets through the same barrel with knife-edge 1/2 MOA accuracy....mind you, a 52-55gr bullet only requires a 1/14 twist to stabilize, so they're spinning TWICE as fast as designed! The incremental increase of bullet rpm say from 1200 fps to 1400fps is negligible, as is the effect on accuracy.

Hi:

Given the same or close to the same velocity, you are correct.

Try shooting your 5.56 bullets in the same barrel rechambered to .22-250 and let me know how your groups hold up.

Sieger

[Sieger]

Originally Posted by Rick W.

what is the twist in a typical vintage 30?

Hi:

The original twist was 9.84 inches.

Sieger

[nukem556]

they'd be just fine....a bullet will shoot precisely, up to the point the rpm exceeds the strength of the bullet jacket and it flies apart in a gray puff 100ft down range....I've seen it happen many times with hotrod 6.5/.284 shooters that push their loads to the ragged edge...the rounds that stay together are in the 10 ring at 1000yds.

[Sieger]

Originally Posted by nukem556

they'd be just fine....a bullet will shoot precisely, up to the point the rpm exceeds the strength of the bullet jacket and it flies apart in a gray puff 100ft down range....I've seen it happen many times with hotrod 6.5/.284 shooters that push their loads to the ragged edge...the rounds that stay together are in the 10 ring at 1000yds.

Respectfully, you can have your own opinion, but 30 plus years of handloading for high-powered rifles tells me differently.

While developing a load, starting low and working up, you eventually reach a spot at which your load is most accurate. Adding more powder, after this point, makes your groups spread out rapidly to the point that you are not even on the paper.

There is a formula for determing proper twist, the Greenhill Formula. Velocity is a major factor in this formula.

Sieger

[Sieger]

Originally Posted by Rick W.

Thanks Sieger;

Always wondered why my 30 caliber bullets from my cheapo home brew barrels hit the paper........occasionally...... :-)

Kinda makes sense, the 10 twist really.

Rick


With super twisty barrels, one might consider a more heavily constructed bullet for some things.

Hi:

Or a longer bullet.

Sieger

[nukem556]

Sieg...I've reading your posts since I joined this great site a little while back, and I've found them cogent and informative. I too, have been loading and shooting lo these 3 decades or so. You are correct, there will usually be a sweet spot for bullet weight/velocity/ sectional density when loading for extreme accuracy in rifles. I've just begun my tinkering with .30 Luger (last project was .25-20 Win out of a Contender, to show you how weird I am!). However, the extremes of ballistic performance from a rifle don't neccesarliy correlate to pistol catridge performance. I've just finishing refurbishing my 1900 Parabellum and have fired some Win and Fiocchi ammo that's chronoing about 1180 fps....its grouping superbly. I'm given to understand DWM specs were around 1250 from the 4 3/4 bbl. I'm going to put together a 6in .30 on another Luger and I'm gonna strive for around 1400-1450 with it...I'll let ya know if it stays on paper

[G.T.]

OK guys.. I really find this thread interesting... But both of you are waaaayyyy beyound me.. I'm still trying to figure out how African swallows got coconuts from Africa to Britain... ... so for the both of you, If you were going to build the ultimate .30 / 7.65 Luger shooter... what twist and bore dia.... .308 or .311 ??? and what barrel length??...... best to all, til...lat'r...GT

[Sieger]

Originally Posted by nukem556

I've just finishing refurbishing my 1900 Parabellum and have fired some Win and Fiocchi ammo that's chronoing about 1180 fps....its grouping superbly. I'm given to understand DWM specs were around 1250 from the 4 3/4 bbl. I'm going to put together a 6in .30 on another Luger and I'm gonna strive for around 1400-1450 with it...I'll let ya know if it stays on paper

Hi:

I learned a long time ago not to argue with success, so feel free to try your hotter loads and see if you can get both accurate groups and good function from your pistol.

If it were me, I'd stick with medium slow powders like Power Pistol, HS-6, AA#5 and SR 4756. You may want to try the slower powders like AA#7 and Blue Dot as well, as there should be enough room in the case for these too.

The original DWM specs. for the 7.65 Parabellum were as follows:

Bullet: 92.6 grs. at a measured (by me) .307 diameter

Cartridge O.A.L. 1.173 inches (round nose bullet)

Powder Charge: Unknown DWM Powder at 5.4 grs.

Velocity from a 4.73 Inch Barrel: 1,150 fps. (350 meters per second)

With a Luger, the impluse created by the cartridge is more critical than, lets say, in a Browning design pistol, to make the pistol function properly. Too light of a load, no function. Too hot of a load, no function. Truly, the cartridge's performance is an integral and critical part of the proper function of this pistol design.

Sieger

[Ron Wood]

Just a thought. Why load up a 7.65mm to hotter specs for "social work"? It doesn't seem like the "stopping power" would be increased, just the penetration. The only advantage I can think of is getting two miscreants to oblige by lining up so one shot gets them both. Now, if you combined the increased velocity with a hollow point bullet that had optimum expansion properties, it might help but then you run the risk of problems feeding from the magazine. As with any self-defense round, the best solution is not the ammo but the expertise of the shooter. Practice, practice, practice…it may not get you a gig at Carnage Hall but it could cause your adversary some grief.

[Michael Zeleny]

Originally Posted by Ron Wood

Just a thought. Why load up a 7.65mm to hotter specs for "social work"? It doesn't seem like the "stopping power" would be increased, just the penetration. The only advantage I can think of is getting two miscreants to oblige by lining up so one shot gets them both. Now, if you combined the increased velocity with a hollow point bullet that had optimum expansion properties, it might help but then you run the risk of problems feeding from the magazine. As with any self-defense round, the best solution is not the ammo but the expertise of the shooter. Practice, practice, practice…it may not get you a gig at Carnage Hall but it could cause your adversary some grief.

That is exactly my thinking. I am planning to develop some loads in conjunction with custom bullets. What intrigues me here is that the W+F P06/29 is the only centerfire handgun I can shoot faster and more accurately than a SIG P210, either in hand or on the draw.

[Sieger]

Originally Posted by Michael Zeleny

That is exactly my thinking. I am planning to develop some loads in conjunction with custom bullets. What intrigues me here is that the W+F P06/29 is the only centerfire handgun I can shoot faster and more accurately than a SIG P210, either in hand or on the draw.

Mike:

Just what "custom bullets" are you referring to, as the selection of 7.65 bullets is very limited?

I note that you live in the L.A. area. Is a right to carry license easy to get out there? If so, I hope you have one before using your Luger for any "social work" as you may just end up being the "criminal" yourself. Also, here, in New York, it is typical for the criminal to sue the shooter for damages, even during the commission of a felony.

Sieger

[Michael Zeleny]

Originally Posted by Sieger

Just what "custom bullets" are you referring to, as the selection of 7.65 bullets is very limited?

Swaging bullets is not hard, and the gear costs a lot less than most good Lugers.

[nukem556]

Well, my intent doesn't involve popping miscreants on the street, I'm looking for a nice flat shooting accurate combo to use in our local pistol sihlouette matches. A lot of guys are moving away from the fancy scoped Contenders and shooting in the iron sight category....to blow my own horn, I won that class in May with my 6in 9mm Luger! The targets are at 30,40, 75 and 100 yds, and I think the .30 would work great.

[Sieger]

Mike:

I've found two fairly interesting bullets for your 7.65mm "social work".

1) Midway USA stocks them (phone number 800-243-3220). It is their Rainier .32 caliber (.312 diameter) 100 grain Plated Hollow Point. You might order some and give them a try.

2) Lee has a 90 grain SWC mold that looks interesting. Its stock number is
TL-314-90-SWC. SWCs are known to cut nice bullet diameter size holes straight through their targets.


Sieger