My 9.3 WON'T CHAMBER

[dragonrider]

And I am thoroughly P--- uhh upset. Quite suddenly my cases won't chamber, it's as though the chamber has shrunken. Odd sounding I know but with a full length sized case it gets very tight as the bolt is being pushed down into battery, so tight that it will not make it all the way. When I remove the case, with difficulty I might add, there is a ring around the center of the case approximately 1/2" wide where it appears the chamber is rubbing on the case, you have heard of ringing a chamber, well this is the opposite. I have changed nothing, same dies, etc. I am most perplexed and don't know what to do. Any ideas???????????

[9.3X62AL]

Kinda weird, that. Have you confirmed that oversized boolits haven't expanded the neck sufficiently to cause tightness at that point? Your comment about the contact point on the case wall doesn't indicate where on the case this occurs......my first thought is that the sizing die may have too much radial clearance at some point. 9.3 x 62 cases and dies that size them are slightly larger than 30-06 based casings, FWIW.

[grumpy one]

Is the rub mark on the cases evenly all the way around? Seems like some foreign object in the chamber could account for it, such as a flattened-out piece of lead, but that wouldn't be all that even around the chamber.

[Larry Gibson]

"with a full length sized case it gets very tight as the bolt is being pushed down into battery, so tight that it will not make it all the way. When I remove the case, with difficulty "

I would ask; how many times have you full length sized the cases and have you trimmed them? I have had the same thing happen with cases that are to long. When the case mouth bumps up against the chamber neck mouth and you force the bolt closed the brass flexes as it must go some where. I've had rub marks from this on the case body of 7.62 cases and 22-250 cases. Most often the case mouth is rubbed or the case head against the bolt but sometimes the case flexes in the middle and rubs there. You might try trimming one of the cases that is a tight fit before you force the bolt down and see if it chambers normally after trimming. Most bottleneck cases stretch .005-.010+" on full length sizing. After several siziings they grow in length a considerable amount. I'd guess that be the problem.

Larry Gibson

[garandsrus]

Dragonrider,

I would certainly check the case length as Larry mentioned... That's an esay measurement to get.

I have had a similar problem when the case wasn't full length sized quite enough and the shoulder didn't get bumped back. With installing and removing dies it doesn't take many .0001's to go from a case that will feed easily to one that is hard to load and bumps the shoulder back when the bolt is closed. You should be able to measure the before loaded and after loaded/ejected (without being shot) shoulder to base length with a comparator of the appropriate size.

I am guessing that a case gague is probably not availabe for that caliber. If I am loading a caliber that I don't have a case gague for, I use the intended rifle/pistol to check that the case will feed properly. I do this both after sizing and after loading the boolit.

One final thought is that you might not be belling the brass quite enough prior to seating your bullet, resulting in the case "collapsing" a little at the shoulder during the seating stage.

John

[dragonrider]

Last night after posting and before go to bed I narrowed it down to case problem. Will figure it out after work today.

[dragonrider]

I determined that the brass was at fault, I was using 30-06 brass trimmed to 9.3x57 length. Still don't know why it happened but if I neck up 8x57 brass I have no trouble. So I tossed the other stuff into the brass scrap pail. Ain't worth getting a headache trying to find the cause.
thanks for the helpful replies

[lmcollins]

I think that you just answered your own question. If you used 30-06 cases to make a shorter case you are useing the 06 case down to were the case walls are thicker than the normal (shorter) case's neck is. If you use a case with a thicker neck you either have to ream the newly formed case's neck or outside turn it. Think about it, and I think that you'll agree with me and see why you had problems.