Ramped Barrel Fit

[texbaz]

I have had my Champion since October 06, and I have really enjoyed shooting it. I wanted to check the barrel alignment. I went to the library and checked out Gunsmtihing by Patrick Sweeney, He explains how to keep the barrel centered in the slide using a fixture when fitting a new barrel, can I assume if I don't have a fixture, that the lugs and the inside edges of the slide can be used to determine barrel centering. His illustration is a non- ramped barrel, does the same process apply for a ramped barrel?

http://img.photobucket.com/albums/v131/texbaz/Champion/Slidebarrelalign4.jpg

In the picture above I'm looking at the distance between the Slide inside edge and the lower lugs are they suppose to have equal distance



Mike

[CJR]

texbaz,

I like to check barrel alignment, relative to the firing pin hole, by using a precision rod that inserts into the barrel and enters the firing pin hole. This rod is available from Brownells. When fitting a new barrel, I'll use the aluminum fixture that fits over the lugs to keep the barrel from rotating when I'm filing the sides of the barrel hood for equal clearance on both sides. For ramped barrels, I fit them so that only the bottom vertical impact area of the barrel hits the vertical impact surface in the frame. I also insure that the bottom of the barrel does not hit any horizontal frame surface during recoil and clearance those horizontal surfaces as necessary.

Hope this helps!

Best rgards,

CJR

[Ericthenorse]

The fixture the book refers to is really nice for fitting the hood of the barrel, and a few other operations.... They are relatively cheap... EGW sells one for $20... http://egw-guns.com/catalog/index.php?cPath=38&osCsid=28f32b2e654a54fa5e0452cc751282a5 And you might be able to get one from Brownells for even less... If you are going through the trouble and expense of replacing and fitting a barrel, go ahead and spring for the fixture... There are also things like lug files that you might need to do it right.....

[deadmarsh]

Alot of ways to skin the cat here, but the bottom-line is you NEED something to assure alignment. If you haven't done this before, the simplest design is the firing pin rod that Brownell sells. Good luck:


Dead

[Ericthenorse]

The rod helps when determining if your barrel is sitting too high or too low... If you are fiitting a new barrel, the rod will not work... It will tell you if your firing pin is centered in the bore, but the lower lugs can still rotate, and you might be way off... The rod is a nice thing to have though.... While fitting top lugs to the slide, it is good to have to make sure everything will work in the end.... You need the block to simulate how the barrel would sit if it was still in the frame...

[deadmarsh]

Eric:

You are correct, to a degree. There are other ways to determine your point, but, and you've been here before as I've seen from your posts, it's much too much to try and describe 'How to fit a barrel' in a few paragraphs to someone who has never done it before. I'm stopping here before we start passing useless tidbits of information between us that we might understand and others might not...

TexBaz, if you listen to Eric, he'll give you some good advice...perhaps a phone call might be the best solution...


Dead

[texbaz]

Thanks for the info, I looked at the prices for the Barrel rod and the block. seems like a few bucks. Maybe I'll just live with what I have for now. Even if I was to try and make the barrel fit just a tad better it probably would have a negative result do to the already smaller than should be barrel hood width. As far a barrel being centering a real rough observation that got me looking into centering is my primer strike was not completely centered but to the side (right) which I thought was odd.
Good info thanks,maybe just better to get another barrel all together, and one that is not a cone/bull config. thanks

[Iron bottom]

The extractor tension can hold the round to the left in the chamber, I've been told. This sounds logical. So getting a perfect firing pin strike is probably almost impossible.

[Ericthenorse]

Tuner is the man to talk to if you want to know how it is really done.... I am still learning this stuff.... :D

I would only ever worry about firing pin placement if I was having a problem with rounds not firing, or I was building a full house race gun or something....

[John]

OK, an I wrong in assuming that the initial question was that the barrel is not centered in the slide in relation to the left and right side of the slide? That has nothing to do with the vertical alignment of the barrel, that's adjusted by the barrel's hood. Texbaz have you filed the sides of the hood at all?

[texbaz]

"OK, an I wrong in assuming that the initial question was that the barrel is not centered in the slide in relation to the left and right side of the slide? That has nothing to do with the vertical alignment of the barrel, that's adjusted by the barrel's hood. Texbaz have you filed the sides of the hood at all?"

John, Here is how I think, it would if the right side of the barrel hood (when viewed from the top of the slide) is touching the slide causing the barrel not sit centered in the slide which in turn would not allow for optimum radial lug engagement. No John I have not filed,

The more I look at this barrel installation it looks as if it was never really fit, but dropped in.

When I insert the barrel into the slide, engage the radial lugs, the barrel tends to list to the left actual measurements support this (this is with the slide just laying upside down on a surface). When I try center the barrel in the slide I feel the side of the hood is already contacting the slide on the right side and it will not center(still laying upside down). when the slide barrel assy is installed on the frame the milled area on the frame where the ramp of the barrel moves back and forth on link down and lock up is being worn down by the barrel ramp . So, my original question was/is:
Can I assume if I don't have a fixture, that the lower lugs outside surface and the inside edges of the slide can be used to determine barrel centering.
Sorry if I'm not very clear. If the answer to my question is yes, my barrel is not centered, I would then muster up a slew of other questions. :D

[Ericthenorse]

That is why I suggest getting the fixture... it will hold your barrel centered and "plumb" so you can check the hood.... I have seen some barrels and slides with radial lugs that are not machined very well. This can sometimes cause the barrel to want to twist....

[John]

I would say that you can trust your measurements. The barrel's feet (or ramp in your case) should be centered in the slide.

[CJR]

texbaz,

Barrel centering, in battery, depends on essentially two contact points in the rear barrel groove making a wedging contact at two places on the rear slide lug. Pat Sweeney shows this clearly for standard barrels in his book, "Gunsmithing". Likewise, in fitting a Kart barrel, which has two raised pads in the rear barrel groove, you CAREFULLY file ONE pad slightly to shift/center the barrel laterally. If you file too much off of the barrel/pad to center the barrel, your vertical lockup will not be so tight on the slide stop. Also if you feel up to it, all barrel grooves can be filed to shift the barrel laterally in the slide. The fitting process requires Magic marking the rear grooves of barrel and the rear lug of the slide, placing the barrel into the slide, and rapping the bottom barrel lugs with a plastic hammer to mark the contact points of the barrel to the slide. You file the barrel to move it in the direction you desire. Checking wth an alignment rod on the firing pin hole helps tell you when the barrel's centered.

When the ramped barrel ramps down, the vertical impact surface of the lower lugs should be the only surface impacting the frame. Any horizontal impact surfaces needs to be clearanced.

Hope this helps!

Best egards,

CJR