Chambering problems-250 Improved(Ackley)

TWOSHOES · October 10, 1999, 06:33 PM

I'm having trouble chambering
some of my reloads. The cases in question were fire-formed in my rifle from new brass. I've re-sized them(full-length) and have trimmed them. These cases have been reloaded three times now. Only a few from the same batch won't chamber.I have not measured the heads. There are no signs of excessive pressure. I would appreciate some advice.

bfoster · October 11, 1999, 09:50 AM

You might measure the head diameter despite there being no signs if pressure. Other things to check are the neck diameter of loaded rounds and also look for burrs (with a magnifying glass) at the case neck: it doesn't take much of a burr to cause a problem. It might also be possible that the brass has taken a "set" (if you have been using really high pressure loads- in better lots of current brass it takes a peak pressure of very near 80,000 psi M43 to cause visible signs of overpressure in some rifles). If you have been shooting "hot" loads I'd check for case thinning just ahead of the web, and measure case length with a Stoney Point comparator or something similar. The problem is that sometimes a full length die needs to be readjusted or have a couple thousandths ground off to size stretched brass enough to chamber properly. An alternative is to grind the shellholder.

A second line of thought is that it might not have anything to do with the case. If you have been using a slow burning rate ball powder it is sometimes possible for deposits to form in the throat and first inch or two of the barrel. If the cases held the bullets snugly & there were deposits you would notice tight chambering. It can be tough to see deposits without a borescope, but if you were to run a very snug fitting patch through the bore and noticed that the rod was considerably easier to push & pull through all of the barrel except the first inch or two you do have a problem. These deposits aren't at all easy to clean out.

TWOSHOES · October 15, 1999, 12:52 PM

Thanks bfoster. Rk10156 suggested I smoke the head.I did this and after chambering a case,I could see a ring around one half of the case about 1/4" above the rim. Incipient head seperation sign? The sizing die I use is from RCBS.It wasn't made by the smith who re-chambered the rifle.Rk10156 suggests this could be a problem.He also suggested that I might be setting the shoulder back too far creating excessive headspace.Originally,I had the die set so that it only re-sized it enough to hold the bullet in the neck.When the empty cases wouldn't chamber,I screwed the die all the way down to the shellplate(Dillon550B).The cases still wouldn't chamber.And yes,I have been using a ball powder(H414).

October 10, 1999, 06:33 PM	#1
TWOSHOES Member Join Date: October 3, 1999 Posts: 33	I'm having trouble chambering some of my reloads. The cases in question were fire-formed in my rifle from new brass. I've re-sized them(full-length) and have trimmed them. These cases have been reloaded three times now. Only a few from the same batch won't chamber.I have not measured the heads. There are no signs of excessive pressure. I would appreciate some advice.

October 11, 1999, 09:50 AM	#2
bfoster Senior Member Join Date: October 13, 1998 Location: N. of Fords Switch, OK, USA Posts: 297	You might measure the head diameter despite there being no signs if pressure. Other things to check are the neck diameter of loaded rounds and also look for burrs (with a magnifying glass) at the case neck: it doesn't take much of a burr to cause a problem. It might also be possible that the brass has taken a "set" (if you have been using really high pressure loads- in better lots of current brass it takes a peak pressure of very near 80,000 psi M43 to cause visible signs of overpressure in some rifles). If you have been shooting "hot" loads I'd check for case thinning just ahead of the web, and measure case length with a Stoney Point comparator or something similar. The problem is that sometimes a full length die needs to be readjusted or have a couple thousandths ground off to size stretched brass enough to chamber properly. An alternative is to grind the shellholder. A second line of thought is that it might not have anything to do with the case. If you have been using a slow burning rate ball powder it is sometimes possible for deposits to form in the throat and first inch or two of the barrel. If the cases held the bullets snugly & there were deposits you would notice tight chambering. It can be tough to see deposits without a borescope, but if you were to run a very snug fitting patch through the bore and noticed that the rod was considerably easier to push & pull through all of the barrel except the first inch or two you do have a problem. These deposits aren't at all easy to clean out.

October 15, 1999, 12:52 PM	#3
TWOSHOES Member Join Date: October 3, 1999 Posts: 33	Thanks bfoster. Rk10156 suggested I smoke the head.I did this and after chambering a case,I could see a ring around one half of the case about 1/4" above the rim. Incipient head seperation sign? The sizing die I use is from RCBS.It wasn't made by the smith who re-chambered the rifle.Rk10156 suggests this could be a problem.He also suggested that I might be setting the shoulder back too far creating excessive headspace.Originally,I had the die set so that it only re-sized it enough to hold the bullet in the neck.When the empty cases wouldn't chamber,I screwed the die all the way down to the shellplate(Dillon550B).The cases still wouldn't chamber.And yes,I have been using a ball powder(H414).