Max Loads & Barrel Life (.243 & .270)?

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blauber

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Well, got my .243 and .270 loads developed. They shoot great out of my Model 700's, and I don't see obvious pressure signs. I have heard that pressure spikes can hurt barrel life, and I reason that pressure spikes might occur when loaded to lands. Here are the loads:

.243: 43.2 gr of IMR 4350 with 85 gr Sierra GK HPBT; OAL=2.664"
.270: 62 gr if H4831 with 130 gr Nosler Partitions; OAL= 3.434"

Do I run the risk of shortened barrel life at max when bullets are seated to touch the lands? How many 1000's rounds can you expect out of a sporting barrel?

I did work up to these loads, and found the best accuracy as above.

Any knowledge welcome on preserving a couple old M700s!
 
Bullets into the lands will create slightly more pressure than jumping the bullets but doubtful that it will affect barrel life significantly. If the barrel will wear out in 1000 rds jumping then you can expect 997 rounds with the bullets jammed.

The .243 is an overbore cartridge and will wear the barrel whether the bullets are in the lands or not.
 
blauber said:
Well, got my .243 and .270 loads developed. They shoot great out of my Model 700's, and I don't see obvious pressure signs. I have heard that pressure spikes can hurt barrel life, and I reason that pressure spikes might occur when loaded to lands. Here are the loads:

.243: 43.2 gr of IMR 4350 with 85 gr Sierra GK HPBT; OAL=2.664"
.270: 62 gr if H4831 with 130 gr Nosler Partitions; OAL= 3.434"

Do I run the risk of shortened barrel life at max when bullets are seated to touch the lands? How many 1000's rounds can you expect out of a sporting barrel?

I did work up to these loads, and found the best accuracy as above.

Any knowledge welcome on preserving a couple old M700s!
Click to expand...

That's a whizzing right along load in the 270 and I'll agree with you on speed. You get a 270 for what it can do, so load it up and shoot. I suppose the barrel life will be shortened a bit, as compared to using 57 grains of H4831, but what the hell. You bought a flat shooting rifle, so enjoy it. If the rifle is for hunting, you will likely never wear it out, anyway.
I also agree on the good accuracy when they are loaded right up.
I say there are a lot more things to worry about in life than how long your rifle barrel will last.
 
If you just use it for hunting, that's an awful lot of bears, deers, and moose before the barrel needs replacing(i'm talking about the .270 now).
 
Thanks gentlemen. Alex-I will play with the calculator, it looks fun. Both are both shooting well and want to keep it like that.

H4831-I have read many, many posts about Jack O'Connor, thanks and I did find that H4831 was the best for my .270 (at least over IMR 4350). I worked up from 59 gr, but found that 62 was great-especially after adjusting the trigger pull.

Is there anything "crazy" with loading these charges at those wts? I have done much online research, but my Lee book says I am over max. I am just over a year into reloading, so don't want to risk anything. I do see a plunger pin mark on the cartridge head with the .243, however this also occurs with lower charges so I don't think it a pressure symptom.
 
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