I just had a moderately close call at the range. I fired some rounds where the brass flowed a bit into the ejector, and required a bit extra force to open the bolt. The signs only showed up as the barrel heated up (about round 12). These were 1/2 grain under max on the Hornady manual, and max in the Speer manual, but without magnum primers (45g H414 with CCI 200 primers, Rem brass and 120 g speer bullets).

When I got home I started investigating found that the cause of the problem was a very short throat on my A&B 260 Rem Barrel. The Speer manual was the only loading source that showed a COL short enough not to touch the lands in this barrel.

My initial load development showed no signs at all of high pressure, but I only shot 3 round groups and let the barrel cool between groups. I guess it pays to not get complacent. I decided to not only seat the bullets deeper on my remaining loads, but also to reduce the powder charge .5 grain.

It's no wonder these loads were so accurate, though. The bullets were being jammed firmly into the lands.

There doesn`t seem to be any fixed lenght to the lead in most manufactures rifles from what I`ve seen. I have rifles with throats long enough one can seat bullets past the max COL and not touch lands, and others that jam before I get close to the listed loaded lengh in the data.
It`s prudent to always check a new chamber to find the true lengh to the lands before starting to load for it, for the reasons you`ve found.

If you are useing an AB barrel perhaps you are useing it attached to a Mod98???

If that's the case get it rechambered to 6.5 X55 and have yourself a desent long necked, long throated cartridge. roger

Fire-lap it. That will fix up the throat and smooth out the bore. Then rechamber to the
6.5 x 55 if you like.

Looking at the case demimsions it looks like you would need to set the barrel back by about 1.25" for a 6.5x55 to clean up a 260 chamber. Am I missing something?

I have a 6.5 throater & T handle I can send you if you want to push the throat a head a little bit.

quote:

Originally posted by ramrod340:
Looking at the case demimsions it looks like you would need to set the barrel back by about 1.25" for a 6.5x55 to clean up a 260 chamber. Am I missing something?

roger Maybe .250"???????

It's on a Savage 110 short action, so I can't go to a 6.5x55 without getting a new bolt and opening up the receiver for a longer magazine.

I did think about fire lapping it. But, I'm not sure it's worth the bother.

Since I plan on using mostly 120 gr bullets the short throat isn't a problem.

I usually make max length mesaurements for every bullet right off the bat - it goes on the first page of the log for that rifle. I guess since it's a new barrel on an old rifle I forgot.

Son of a gun! Those short actions suck; don't they? roger