243 puzzle opinions welcome

[gazzar15]

I recently bought a Cooper arms 243 .A mate owns one and he achieves one hole accuracy at 100 yds and with reloads regularly achieves .5 moa accuracy. I took mine to the range and fired off my first shot.It was a bit tight to close the bolt.Round 2 I used a bit of pressure to close the bolt fired the shot and could not open the bolt.I gave it a good slap with the palm of my hand and the bolt handle came off.I might add at this point that the rounds I used were home loaded by myself COL was 2.700'' with the cases trimmed to .005' under the stated trim to length and they all function flawlessly in my 243 Heym.I have had the bolt repaired correctly and without a round it functions as it should,try again with a dummy round loaded to the above dims and a repeat of the problem ,However reduce the col to 2.650 and the bolt cycles the cartridge perfectly.This means a tight chamber yes???I bought the gun used and to be honest it looks like it has done precious little work.If the previous owner had a similar problem I think he may have gotten fed up with the rifle and pushed the bolt to almost the point where it broke by giving it the mallet treatment.I probably suffered the aftermath after the previous owner got shut.Is it then possible to have 243 chamber this tight???

Opinions please gents

Gary

[Vermincinerator]

Its common for reloads worked up in one rifle not to fit in anothers chamber, it is most likely that the Cooper will have been cut with a minimum SAAMI Spec chamber which will operate with all factory ammo but cases from shot in another rifle which may have a slightly looser chamber will not fit the Cooper.

I have always worked with the rule, New rifle = New brass

 

Ian.

[baldie]

Ian is spot on there Gazza.

The cooper will undoubtedly have been cut with a minimum saami spec reamer, as they are more of a large custom shop than a mass producer. The cases from your heym could be too fat, but they could also have the shoulder too far forward.Both will cause problems like you have encountered.

Always FULL length size brass that hasn,t been fired in that particular gun, whether its brand new, or fired in something else. I,m like Ian personally, i always use new brass in a new gun.