10-26-2023, 01:01 AM
If it takes more than 8 to 9 pounds of pressure on the back of the carrier for the bolt to close on a go gauge, then the chamber is too short..
Chambers can also be cut to narrow that can be identified with a function gauge. Most gunsmiths and armorers don't carry these... I have a 5.56 Faxon barrel with this problem that I keep as an example..
Lapping the bolt lugs can sometimes correct a short chamber that is near the edge of passing, but if the bolt and barrel were sold as one unit then it is best to send it back to the manufacturer..
I will (respectfully) disagree with Klem's statement about the chamber being shorter than SAMMI is OK, but it isn't the first time we have disagreed lol..
Best to have the chamber meet the minimum go gauge set by SAMMI so there is zero chance of pressure spikes with any types of ammunition that may be on the edge of size or pressure..The other factor is when a chamber heats up, the chamber gets tighter compounding the problem..
Tight chambers can create accuracy problems (erratic pressures), popped primers and reliability problems..
Chambers can also be cut to narrow that can be identified with a function gauge. Most gunsmiths and armorers don't carry these... I have a 5.56 Faxon barrel with this problem that I keep as an example..
Lapping the bolt lugs can sometimes correct a short chamber that is near the edge of passing, but if the bolt and barrel were sold as one unit then it is best to send it back to the manufacturer..
I will (respectfully) disagree with Klem's statement about the chamber being shorter than SAMMI is OK, but it isn't the first time we have disagreed lol..
Best to have the chamber meet the minimum go gauge set by SAMMI so there is zero chance of pressure spikes with any types of ammunition that may be on the edge of size or pressure..The other factor is when a chamber heats up, the chamber gets tighter compounding the problem..
Tight chambers can create accuracy problems (erratic pressures), popped primers and reliability problems..