I recently bought a contender carbine in 17 mach IV from Bullberry. When I got the barrel, I noticed the lug was sticking too far back from the back of the barrel to allow it to close. I sent it back and it was machined down. I got it back today, and when forming cases from new RP 221 fireball brass, the case will not chamber. I did not use the expander plug so I know the neck is not causing the problem. I screwed the sizer down far enough to set the sholder back and allow the case to chamber, but setting the shoulder back that far puts a dent in the case right behind the shoulder. I think my chamber was cut too short. I e-mailed bullberry today and may end up sending the barrel back again. Any ideas? Thanks.

Ranb

I have an idea: stop buying barrels from someone who doesn't pay attention when they are making them!

Both of those problems should have been caught before leaving the shop.

George

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Shoot straight, shoot often, but by all means, use enough gun!

DUH!!! So what if the chamber is not too short? Am I forming the cases properly? I found that by setting the shoulder back with the form die before running it through the sizer, I can get it peoperly sized to fit in the chamber.

Ranb

Fireform one of the cases you've sized down, and take measurements (overall length, neck length, case head to shoulder, case head to shoulder/neck junction). Post them here and we'll compare them to a fully-formed case.

George

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Shoot straight, shoot often, but by all means, use enough gun!

I got an e-mail back from bullberry and he states that setting back the sholder and fireforming is the only way I will be able to fit a case properly in the chamber. Sounds ok to me. My biggest problem now is getting a uniform neck wall thickness on my lathe. The wrinkle created is not very uniform. This makes the case a bit crokced and the neck turning a problem.

Ranb

Ranb,
Try turning the case necks before sizing down to .17.

George

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Shoot straight, shoot often, but by all means, use enough gun!

I got the neck turning part figured out. I made a mandrel that is .174". This holds the brass very tight while turning it on the lathe and my necks walls are always within less than .001" I was holding the case rim in the work holding chuck and the mandrel in a tailstock chuck before. This did not work at all. I will hit the range today and see how well they fireform. I will post the dimensions of a fired case. Thanks for the advice guys.

Randy

Just got back from the range. The brass formed nicely in the chamber and was rather accurate for a fireforming load. I got 3500 fps with a stdev of 7 fps. 6 shots went into a 1.5 " group at 100 yards with 4 holes 3/4" apart. The fired brass dimensions are, rim to shoulder-1.062", neck-.179" total length-1.386", head diameter-.375". A very good start I think. Thanks for the help guys.

Ranb