7mm RM barrel life?

[WVHILLBILLYJLM]

Hello, I am not a target shooter but enjoy the information from this site alot and I need some input.

I have a Rem 700BDL SS in a 7mm RM and I had been shooting handloads consisting of IMR4831 and Nosler B-Tips. I recently determined that I lost a considerable amount of velocity.The loss was about 300FPS. Could temperature cause this much variation?

I also determined that my throat had extended about 0.12". Could this be the problem? What is the average barrel life of a 7mm RM? I have put between 700-800 shots threw it.

Any suggestions?

Thanks,
WVHILLBILLYJLM

 

[billmo]

Are you sure it has moved one hundred and twenty thousandths? Or were you meaning twelve thousandths? That is a whole lot of movement in 700 to 800 rds. fired. I'm thinking that barrel should go at least to 1500-2000 rds. if heat is kept down and barrel is kept clean,copper and carbon removed) That is a whole lot of loss for temp. changes too. Did you change powder lots? Are you sure your scales are O K? Just some things to look at.
Bill

 

[WVHILLBILLYJLM]

Billmo, I am sorry but I made a mistake. I went and looked at my notes and remeasured for confirmation. My overall length shows that the throat has extended by 0.074". I determined this by originally setting my seating depth by just slightly touching the lands, now I had to seat the bullet 0.074" longer. Is this a correct or acceptable way of measuring because I do not have a COL gauge.

I did switch powder lots but the new lot had no affect on the velocity of the 300Wby that I also load for. Could the different deminsions of the cartridge cause the powder to act differently.

I use digital scales and I recalibrate after every third round. I also confirm by weighing a known bullet weight.

Sorry for so many questions, as you can tell, I am a beginner at this.

Thanks,
WVHILLBILLYJLM

 

[billmo]

Man, I think you need to be able to measure COL to lands more accurately. No, I don't think the powder is the problem. I use digital scales for all my handloading with no problems. Get a hold of something to measure the COL with and make sure your readings are correct. Bill

 

[patchhound]

You might want to take the gun to somebody with a bore scope and take a good look down that tube. SS might be a bit better for a factory bbl. but I COOKED my old 7rm blue bbl w/ around 700 shoots. If your fouling up bad and losing acuracy too Ide say she`s done, if not, w/ 70+ thou. gone from the throat you might get 200 maybee. Ide start lookin into a new bbl now and have it ready.