fast powders and barrel life

[davkrat]

Do lighter loads of a faster burning powder have less effect on barrel life than max loads of slower powder? I like to load light practice/plinking loads in my 270. Currently I am using H4831 behind 110gr VMax. I just bought a.308 and hope to get good results with Varget in it. On Hodgdon's site Varget is one of the faster powders they suggest for the 270.

For a 130gr Max loads are:

60gr. H4831
46gr. Varget

That's 25% less powder with the Varget and slightly lower pressure. What has the biggest effect on burning up a barrel velocity, pressure, or amount of powder burned? Like most things it is probably a combination of all. Thanks

 

[Mikecr]

I think powder amount trumps all else in barrel life. Otherwise some people would burn out barrels chambered 223Rem as quickly as 220 swifts. As an extreme example.

But it may be possible to adjust a load using cooler/slower powders in a cartridge for better barrel life. This might take a chambering with slightly more capacity.

 

[rotorhead]

I will touch on this one, You ask if the powder burn rate makes a differance... If I understand correctly the temperature that the powder burns and the longer it burns in the throat will predict the barrel life. So double based burn hotter and single base is cooler. A heavy bullet is harder to push down a barrel so the powder burns longer at the throat.
If I'm right and I think I am this is how it works. You are shooting a 270 It will take alot of rounds to smoke your barrel. I think if you want a lighter round for pratice thats ok but I practice with what I shoot for real this way I can learn the rifle and the load and most importantly the point of impact at all ranges.
I'm not real sure if I helped you or not I've only had a couple cup of coffee so far.

RH

 

[davkrat]

rotorhead,
Thanks for the response. Let me explain what I mean by practice rounds. I only have one gun, my 270. I just paid for a .308 but have to wait the CA 10 days. I don't think there is any practice in the world that can replace pulling the trigger. Ideally I would have a couple big long range guns, a few medium bores and then a varmiter or two. I could then take several guns to the range and shoot to my hearts content. I'm sure there are many that would laugh at the thought of a 270 giving much recoil but after about 20 full power shots it starts to creep into my head. Before anyone starts to picture me as a light weight sissy let me tell you that I am 6'2" and weigh 275lbs., I just have a mental tendency to flinch. I think bouncing a poorly mounted shotgun off my cheek too many times hasn't helped but when those teal go whipping around behind you and you're slipping in the mud wearing every jacket you own it can be a little tough to get a perfect mount /ubbthreads/images/graemlins/wink.gif

In the past I tried the Sierra 90gr and now use the 110gr Vmax. I try to load them to a mild velocity that gets the best accuracy. I did a ladder test a few weeks ago and 4 or 5 charges went into a 1/2" which seems like a pretty good node to me. The 110s at a mild velocity are plenty strong for ground squirrels. The powder I tested was H4831 but I am guessing that faster burning Varget with 3/4 as much powder might lead to longer barrel life. I've always been a one gun kind of guy, I think being real familiar with your gun is a real bonus.

I don't really intend to shoot the 110's much past 200 yards so it's basically a dead on hold and trajectory differences don't really matter. I wouldn't try to hit anything at any real distance with these loads. I'll try the Varget out as I plan on getting some for the .308. I probably won't smoke the barrel out of either of them anytime soon.

To summarize a lighter bullet that spends less time at the throat and a lower charge of a faster burning powder should add up to less erosion of the throat. At any rate I think I'll stick with my light plinking loads for busting squirrels inside 200 yards. Thanks