Contender barrel not liking longer bullets?

[parallaxbill]

Anyone else experiencing their 41 magnums not chambering much over 210 gr WFN cast bullets? My 250 gr cast performance bullets will not chamber. Is that normal for these barrels?

[bradshaw]

Jun 3, 2022 18:05:41 GMT -5 parallaxbill said:

Anyone else experiencing their 41 magnums not chambering much over 210 gr WFN cast bullets? My 250 gr cast performance bullets will not chamber. Is that normal for these barrels?

*****

It was standard practice at Thompson/Center to ream Contender barrels with a freebore. The Contender is about the easiest in which to make a Cerrosafe casting. Short of that, drop in a bullet; tap it with dowel to engrave rifling (or tight spot). Engraved bullet may contain answer.
David Bradshaw

[contender]

David is right. T/C had a habit of a good freebore. Now you are gonna make me play with my Contender bbl & longer bullets.

[cas]

You may have free bore, and it's just smaller than your bullets?

(Sorry I only have a tiny bit of T/C .41 mag expericnace and it was an Encore and a customer barrel)

[parallaxbill]

All I know at this point is that it wouldn't chamber 265 gr Underwood factory loads so I dropped to 250 only to find that they wouldn't either.
I've got some 200 WFN to try next.

[potatojudge]

I have a factory 41 reamed to 414. It chambers heavy 41 just fine but the chamber extension from 41 to 414 was cut slightly undersized for cast, so it isn't much of a 414 really. Guess I should see how jacketed bullets fit, but with bullet weight limitation why bother?

[parallaxbill]

All of my Whitetail kills with my 10" T/C have been with jacketed bullets from 170-200 gr. But I would prefer killing them with hardcast. 200 or 210's might be plenty good enough. Our SC bucks rarely go much over 200 lbs.

[rkrcpa]

Jun 3, 2022 18:05:41 GMT -5 parallaxbill said:

My 250 gr cast performance bullets will not chamber. Is that normal for these barrels?

My 41 mag barrel closes on a 250gr WFNGC

[parallaxbill]

The pen is pointing to where my 250's are contacting something. The Underwood 265 LNFP actually contacts close to the case mouth before contacting. But neither will close in my Contender barrel.

[rkrcpa]

Jun 7, 2022 9:07:00 GMT -5 parallaxbill said:

The pen is pointing to where my 250's are contacting something. The Underwood 265 LNFP actually contact close to the case mouth be for contacting. But neither will close in my Contender barrel.

The profile of your 250gr WFNPB is considerably different from my WFNGC.

[bradshaw]

I would measure SEATING DEPTH with a Sierra, Hornady, etc., jacketed bullet of established quality. Measurement from breech face to front of bullet wheelbase (bearing surface) = seating depth. Blacken bullet with felt-tip pen. Until we know diameter of cast bullet it’s impossible to opine chamber irregularity. An poor ream job may be at fault. A Cerrosafe cast of chamber will reveal irregularity, provide for pretty good measurement (follow instructions), and----important----show LEADE (transition angle from throat to top of LAND).

A micrometer measurement of bullet diameter, taken at several diameters and several places along bearing surface, provide picture of bullet diameter & roundness.
David Bradshaw

[parallaxbill]

Some measurements to consider with this 250 gr CPBC WFNPB and where the rifling is first making contact on the bullet nose. Where I pointed out with the pen in the previous photo.

COAL=1.667"
Bullet diameter where the rifling makes first contact is=.405 +or- .00025
Length from cartridge base to first contact of bullet nose with the rifling=1.500"
Bullet driving band=.410'

I'm thinking the problem is the profile of the bullet as it seems to be with the Underwood 265 LNWFP

[x101airborne]

You are one of the lucky few that has a barrel with little freebore. I bet it shoots standard weight bullets very accurately. Personally, I would trade out or buy another barrel before reaming that one. I certainly would not alter that barrel. Plenty others out there that have three times that amount of throat to them. I have a 44 mag barrel that we reamed out to 444 Marlin before we ever reached full lands.

[parallaxbill]

I agree, since my OM 41 magnum will shoot the big bullets I will stick with the lighter ones in the T/C. And yes, it is very accurate.