Barrel specs

sw1115 · May 03, 2016, 02:30:43 PM

Hi, does anyone know where I can find a diagram for a .177 Crosman barrel. I'm looking for the chamber specs (length of leade, dia, TP location ect.)

Thanks
Skip

quickster47 † · May 03, 2016, 03:27:04 PM

Quote from: sw1115 on May 03, 2016, 02:30:43 PM
Hi, does anyone know where I can find a diagram for a .177 Crosman barrel. I'm looking for the chamber specs (length of leade, dia, TP location ect.)

Thanks
Skip

I have never seen the specs for either a Crosman .22 or .177 caliber barrel but would also be very much interested as I am in contact with Lothar Walther about making me a titanium barrel for my 2240 Lite project.

Carl

JMJinNC · May 03, 2016, 03:50:03 PM

This?

CraigH · May 03, 2016, 03:57:35 PM

Wow, ask and ye shall receive!

Do you also have the .22 spec, John? TIA if so. (probably similar or the same except for bore diameter)

quickster47 † · May 03, 2016, 03:59:40 PM

Wowee, thanks a 1000 times over Mister John.

Carl

JMJinNC · May 03, 2016, 04:00:55 PM

Think this is it. JMJ

ped · May 03, 2016, 06:53:11 PM

the 1377 barrel spec is it the earlier phase 1/2 1377 leade dimensions

JMJinNC · May 03, 2016, 07:42:25 PM

I found these specs on the yellow forum a long time ago. I used it to machine the barrel for my LW66 project. I did verify the dimensions based on the 24" barrel I got from Crosman (as much as could be measured, anyways.).

JMJ

CraigH · May 03, 2016, 07:56:41 PM

JMJ, Thanks for the .22 caliber chamber spec.

The two drawing show quite different designs. The .177 seems to have the rifling continuing rearward of the transfer port. The .22 has the rifling stopping well forward of the transfer port and so a much longer chamber. I image a lot could be done to create a custom chamber for specific pellets and needs. Have to do some measuring and thinking.

JMJinNC · May 03, 2016, 08:27:38 PM

No problem. If you have a .22 Crosman barrel handy, I'd suggest making a mold of the leade using caulk or wax, perhaps (we use dental casting compound at work). Then you'll have a much better idea of what the leade looks like.

JMJ

sw1115 · May 04, 2016, 03:14:29 AM

Thank you very much John. I'm going to pull my .177 and see if the rifling does extend past the TP. I would have thought there would be some free bore before the pellet entered the lands.

Skip

sw1115 · May 04, 2016, 03:26:33 AM

John, when you built the LW66 project did you have a reamer made or did you go in "free hand" so to speak. I think it would be tough to check the depth of the angles in the bore.

Skip

JMJinNC · May 04, 2016, 03:37:37 AM

IIRC, I found a 20 degree reamer and got as close as I could to the shown leade depth, then made the counterbore with a boring bar. Nerve-wracking on a virgin LW barrel, but I got it within a few thousandths.

I finished the leade with some polishing. Could use some more, but pellet loading is smooth and the accuracy is as good as my other LW barreled Avanti.

JMJ

sw1115 · May 04, 2016, 03:51:37 AM

I think I might practice on some crosman cut offs before I venture in to the LW.

Skip

ped · May 04, 2016, 10:55:13 AM

when I do barrels I just use a tapered reamer and if using an o ring on the probe keep testing till I have enough depth for it to lock up and seal
these days I prefer to fit the o ring in a pocket in the barrel so it's trapped between the barrel and breech as then all you need is a smooth transition to the rifling