Artillery Barrel Specs???

sheepherder · 03-09-2009, 08:53 PM

1st pic here is reaming the chamber for 9mm Parabellum, with a Clymer finishing chamber reamer and floating reamer holder. I've determined that I only need to cut another .018" to get my desired headspace.

Clymer recommends high-Sulphur content cutting oil; 1/32" cut at a time; chips blown out between cuts.

2nd pic shows the reamer fully inserted; final cut.

3rd pic is barrel back on receiver w/notch cut and chamber finished. Fully assembled, almost ready to shoot...

...but the barrel still needs the feed ramp milled...

I could shoot it one shot at a time...and stick the cartridges in by hand...but I can wait...

Edit: Pics updated to show how it *should* have been done, rather than the clumsy way I did it.

sheepherder · 03-09-2009, 09:58 PM

I just know that someone is going to ask how I figured out the correct amount to remove for my desired headspace...or why I reamed a chamber back in the initial stages...

It's because the way this pistol is constructed, headspacing a partially reamed chamber is pretty simple...at least, it is the way I do it...

First I strip the breechblock of ejector and firing pin. 1st pic shows stripped breechblock/toggle assembly, axle pin, squib rod, and barreled receiver.

2nd pic shows assembled breechblock/toggle/axle pin assembly mounted in barreled receiver, with the squib rod applying light pressure against the breech face. (You can just see the rod in the chamber and at the muzzle).

3rd pic shows measuring the gap between the receiver and the breechblock with a feeler gauge (still with light pressure on squib rod). It's .035" on this assembly.

4th pic shows a sized cartridge [.754" OAL max] inserted in the partially chambered barrel, and the toggle assembly pressing against the cartridge. The gap between receiver and breech is measured again (with feeler gauges), and the difference between this and the previous measurement, plus the amount of headspace desired, is the amount to be reamed with the Clymer finishing chamber reamer. In this case, it was .018".

With the barrel again removed from the receiver, I just measured the length of the chamber (from where the cartridge mouth locates) to the chamber rim, chucked it up in the lathe, and reamed it down the required .018".

To avoid discussion, I didn't specify what headspace I used here, because this is a commercial model, and whether it's headspace is different from the military model or not, I like a tighter headspace than what I usually find on production pistols.

Rube Goldberg Lives!!!

Edit: Thanks to Rick W for noticing the goof in the amount of material to be removed.

sheepherder · 03-10-2009, 07:30 AM

I'm cutting the feed ramp now...

1st pic - I center the [stripped] barreled action in the mill vise, and set it to what I think is the desired angle...

2nd pic - I've eyeballed an old P-08 9mm barrel throat, and made my cut with a 3/8" end mill...here's the result...

3rd pic - Barreled action has been reassembled and weapon is fully functional once more

...Sharp chamber edges still need to be smoothed out; tool marks on outside of front barrel band, rear sight 'sleeve', and rear sight base need to be draw filed or sanded, and the rear sight itself needs some more work...but it should feed and fire now...

I'll reload some dummy rounds (no powder/primer) and see how it cycles...Might have to adjust the feed ramp angle...

...But in one of those annoying occasions, I can't find my 9mm shell holder...

I'll have to get up to the local sporting goods shop and get another one...

I have 5 or 6 hundred 9mm rounds reloaded, but they're loaded hot for my S&W 659...I don't want to chance blowing the ejector through the breechblock, so I'll wait and load some light rounds to try this booger out...

sheepherder · 03-10-2009, 07:39 AM

BTW: I'd like to thank the owners and moderators of this forum for hosting this brief "HowTo". I understand that this is a Collector's Forum for P-08 Lugers, and that many would consider this type of modification to be blasphemy...

So a big "Thank You!" to all of you!

(And if anyone ever finds a copy of the LP-08 specs/blueprint, I sure would like a copy!)

03-09-2009, 08:53 PM	#1
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,197 Thanks: 1,416 Thanked 4,462 Times in 2,336 Posts	1st pic here is reaming the chamber for 9mm Parabellum, with a Clymer finishing chamber reamer and floating reamer holder. I've determined that I only need to cut another .018" to get my desired headspace. Clymer recommends high-Sulphur content cutting oil; 1/32" cut at a time; chips blown out between cuts. 2nd pic shows the reamer fully inserted; final cut. 3rd pic is barrel back on receiver w/notch cut and chamber finished. Fully assembled, almost ready to shoot... ...but the barrel still needs the feed ramp milled... I could shoot it one shot at a time...and stick the cartridges in by hand...but I can wait... Edit: Pics updated to show how it should have been done, rather than the clumsy way I did it. Attached Thumbnails Last edited by sheepherder; 03-11-2009 at 05:38 AM.

03-09-2009, 09:58 PM	#2
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,197 Thanks: 1,416 Thanked 4,462 Times in 2,336 Posts	I just know that someone is going to ask how I figured out the correct amount to remove for my desired headspace...or why I reamed a chamber back in the initial stages... It's because the way this pistol is constructed, headspacing a partially reamed chamber is pretty simple...at least, it is the way I do it... First I strip the breechblock of ejector and firing pin. 1st pic shows stripped breechblock/toggle assembly, axle pin, squib rod, and barreled receiver. 2nd pic shows assembled breechblock/toggle/axle pin assembly mounted in barreled receiver, with the squib rod applying light pressure against the breech face. (You can just see the rod in the chamber and at the muzzle). 3rd pic shows measuring the gap between the receiver and the breechblock with a feeler gauge (still with light pressure on squib rod). It's .035" on this assembly. 4th pic shows a sized cartridge [.754" OAL max] inserted in the partially chambered barrel, and the toggle assembly pressing against the cartridge. The gap between receiver and breech is measured again (with feeler gauges), and the difference between this and the previous measurement, plus the amount of headspace desired, is the amount to be reamed with the Clymer finishing chamber reamer. In this case, it was .018". With the barrel again removed from the receiver, I just measured the length of the chamber (from where the cartridge mouth locates) to the chamber rim, chucked it up in the lathe, and reamed it down the required .018". To avoid discussion, I didn't specify what headspace I used here, because this is a commercial model, and whether it's headspace is different from the military model or not, I like a tighter headspace than what I usually find on production pistols. Rube Goldberg Lives!!! Edit: Thanks to Rick W for noticing the goof in the amount of material to be removed. Attached Thumbnails Last edited by sheepherder; 03-10-2009 at 07:16 PM.

03-10-2009, 07:30 AM	#3
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,197 Thanks: 1,416 Thanked 4,462 Times in 2,336 Posts	I'm cutting the feed ramp now... 1st pic - I center the [stripped] barreled action in the mill vise, and set it to what I think is the desired angle... 2nd pic - I've eyeballed an old P-08 9mm barrel throat, and made my cut with a 3/8" end mill...here's the result... 3rd pic - Barreled action has been reassembled and weapon is fully functional once more ...Sharp chamber edges still need to be smoothed out; tool marks on outside of front barrel band, rear sight 'sleeve', and rear sight base need to be draw filed or sanded, and the rear sight itself needs some more work...but it should feed and fire now... I'll reload some dummy rounds (no powder/primer) and see how it cycles...Might have to adjust the feed ramp angle... ...But in one of those annoying occasions, I can't find my 9mm shell holder... I'll have to get up to the local sporting goods shop and get another one... I have 5 or 6 hundred 9mm rounds reloaded, but they're loaded hot for my S&W 659...I don't want to chance blowing the ejector through the breechblock, so I'll wait and load some light rounds to try this booger out... Attached Thumbnails

03-10-2009, 07:39 AM	#4
sheepherder Lifer Lifetime Forum Patron Join Date: Feb 2009 Location: ...on the 'ol Erie Canal... Posts: 8,197 Thanks: 1,416 Thanked 4,462 Times in 2,336 Posts	BTW: I'd like to thank the owners and moderators of this forum for hosting this brief "HowTo". I understand that this is a Collector's Forum for P-08 Lugers, and that many would consider this type of modification to be blasphemy... So a big "Thank You!" to all of you! (And if anyone ever finds a copy of the LP-08 specs/blueprint, I sure would like a copy!) Last edited by sheepherder; 03-10-2009 at 07:45 AM. Reason: just tidying up