my .243 barrel

[mjbgalt]

i have a browning a-bolt that i absolutely love. i reload for it and the best shooting load i have is 40.5 grains of Varget under a 60-grain Sierra hollowpoint. by estimates (no chrono) based on velocities listed in the LEE reloading book, this load screams out the end of my barrel at about 3,700 fps.

it shoots into less than a half inch. in fact, this rifle (when i am on my game) can put three shots into 0.300 of an inch. i am very happy of course.

the issue is that when i chamber the rounds, i can see upon ejecting them that the bullet is not only touching the rifling, it is actually putting a slight mark on the bullet, i can see the grooves in the bullet's shiny jacket.

is this bad? i know it CAN lead to high pressure...but i have zero high pressure signs in this rifle, and as i said, it shoots very well.

also, am i burning out the rifling like crazy by doing this? it seems it would be better to have it this way than to seat the bullet lower and have it ping-pong around when it hits the rifling until it gets in the right position and goes down the barrel. also, the load is at the minimum overall length for the cartridge, so it's not like i should seat it lower, right??

-Matt

[cwlongshot]

By having the bullet IN the rifling you are raising the pressures dramatically. More accurately, causing a pressure spike.

Yes, you should seat the bullet deeper so the bullet is at least .005 off the rifling.

 The cartridge OAL is a std, if your bullets length is truly correct, you have a short leade in your barrel. The ogive or profile of your bullet is a better way to figure cartridge OAL for a perticular rifle, than just a OAL woth out reguard for bullet profile.

In any case, as a rule your bullet SHOULD NOT be in the rifling.

CW

[victorcharlie]

My .243's shoot their best with the bullet touching the lands of the rifleing.....and my best load is one grain below max in the older manuals but 2 grains over max in some of the new manuals........been shooting this configuration for 20 years with no problems.  No flattened or pierced primers and no sticky bolts.....not much in the way of extractor marks on the head either.......case life is about 5 loads per case.

Load is IMR4831 and sierra 85gn BTHP...........