FTF Kimber/Brown bbl.

[greekgod56]

No problem using kimber bbl/bush with any type of bullet. Went to Brown bbl. as I was not satisfied with accuracy. Using lswc and lswcbn bullets the round looks like it travels up the feed and barrel ramps and hits the top of the chamber damaging the bullet and then the slide jams the case against the bbl ramp approx. 1/4 in from the case rim on the side of the case against the ramp. Leaves marking on case. I've tried Gi mags, Mec-Gar mags, Kimber mags with flat and round followers to no avail. If the 1st. round does happen to chamber properly then the next round when fed will jam. Is this the classic 3 point jam ? If so, what can I do to correct problem ? Lock-up, hood/breech clearance, lock down clearance between bbl and receiver feed ramp (1/32"), etc. all check out. Will jam occasionately with round ball but every timw with swc. BBL is supposed to be throated for swc and was installed by local smith who said he had no problem with hardball but didn,t have any swc to try. Would appreciate being led down the right path !! Thanks in advance

[John]

Well, it appears that you have the classic 3-point jam. If the pistol works with the standard barrel and bushing, it has to be something with the barrel. Remove the slide from the frame, take out the barrel and put it on the frame. Pass the slide release through the link hole and insert it in the position it will be, when the barrel is on the pistol. Push the barrel back and down so that it lays on the frame bed. Snap a couple of pictures so that we can see the ramps and their relationship. Do the same with the barrel that works so we can compare.

My guess is that the barrel ramp is not at the right angle, but we'll wait to see the pictures.

[greekgod56]

picshttp://i145.photobucket.com/albums/r206/greekgod56/DCP00634.jpg

[greekgod56]

TRy again..http://i145.photobucket.com/albums/r206/greekgod56/DCP00632-1.jpg

[John]

Post some pictures (from the same angles) of the barrel that came with the gun. It looks OK from here. One question, how does it work with standard factory FMJ ammo? And what's the specs of your reloads compared to the 230 gr ball? Especially the OAL?

[twin oaks]

2nd pic, 6 and 7 o'clock. Looks like slight bur or pitting at the edge. Is it? I had similar problem with a ramped barrel in a Sig w/ swc's. My prob was that the bullet itself was the issue, the edge of the swc causing the snag. Along with pics, color the ramp and throat w/ marker to see where the rub is. You might also try it with the bullets themselves. My only solution was to go to a truncated cone bullet.

[twin oaks]

P.S. Did the 'smith alter the ramp dimensions when he fitted the barrel?

[niemi24s]

To my aging eyes, it looks like the receiver's feed ramp is rounded over at its top where it meets the barrel bed. Could be the lighting or the slightly out-of-focus pic too, but . . .

GG56: The ramp and bed should meet and form a nice sharp corner; has this corner been rounded over?

[greekgod56]

First, let me thank all of you who have taken the time to help with the problem. In answer to some of your questions ; there is no burr or rounded edges on the ramps. That is caused by the light and not so great pics. I called Brown products and told them of my problem. They were very respectful and courteous. Said that the throat may need opening up a bit more but without looking and measuring the barrel they were ball- parking (my term).They offered to take a look at the barrel and would get back with me. However, I took the pistol back to the smith that had fit the barrel for me. I know him personally and he has done quality work in the past for me. Showed him the rounds that had jammed and we came up with what may be the answer. The marking on the cases was caused by the sharp edge where the barrel ramp and chamber meet. The extractor was causing the bullet to hit the top of the chamber and at times not engaging the case rim. So here is what we basically came up with. radius the sharp edge in the chamber, "tweak" the extractor, and clean up the bbl. ramp. According to the smith this is not an uncommon problem especially with guns that use wadcutters. As soon as the work is done i will post my findings. One more thing, John was right on my OAL on some of my rounds. They were too short. Now some will say that I should have taken the gun back right away. This was to me a "learning experience " albeit quite frustrating.

[niemi24s]

Your 'smith deserves a pat on the back for catching the sharpness of the barrel ramp/chamber intersection. Gov't barrel blueprints specify breaking this sharp corner with a 0.020 inch radius. This provides for easier cartridge entry into the chamber when the round hits the top of the chamber - and it's inevitable that the round will hit the top of the chamber.

The other problem he noticed (extractor hook not always engaging the case rim) could be caused by a weak magazine spring - or a few other things your 'smith probably knows about.

Sounds like the fix is in the works - let us know how it turns out. Cheers

[John]

Yeap, contrary to the frame bed - frame ramp edge, which should be sharp, the barrel ramp - chamber edge should be veeeeery slightly rounded. Just scrap it with a knife a little to remove the sharp edge is usually enough.

As for the extractor, either too much tension on the extractor, no polished lower surface can stop the rim of the cartridge from going under the hood. Burrs on the breechface can have the same effect.

[twin oaks]

One other thing to check is the angle your magazines are holding the round. 'smith friend of mine said he's had similar probs with some mags holding too flat for swc's.- ( like a follower with no dimple). Sounds like you got it beat though.