Home Forums Reloading Big Game Rifles .270 win throat erosion

I checked the distance to lands measurements on my pre 64 fwt.270 today and the throat appears to have moved forward about 0.035" over the past 900 shots or so, mostly 130's at 3000 fps over RL22. Accuracy is still fine and I will be adjusting my seating depth but I am curious if this is in line with what others here have noted.
Thanks
Mike

RL 22 has a reputation for eating 270 throats more than H4831sce or H 4350.

I've never measured one....but they just stop shooting consistently IME.They drive you hoopy with inconsistency.Good group today and tomorrow not so hot and so it will go.This is when they are getting close to the end.

What RinB said.

I've been lucky enough to shoot the barrels out on two .270's.

Interesting regarding RL22 comment. Never heard that before.

I would like to see some data on this. Seeing how H-4831 was introduced in 1947 specifically for the 06 family of cases. And it was actually a mil surp powder. 4831 SC wasnt introduced until about 1990 to 95. Hercules didnt introduce the Reloader 22 powder until after 1969 when it obsoleted the reloader 21. So seeings how the 4831 family had 25 years or so on it for usage, and the fact that 4831 and 4831 SC are exact except for kernal length, more clarification is needed on this staement.

Thanks for the replies.

I believe the RL22 comments would apply to double based powders in general and doesn't surprise me. That is why they tend to give more velocity. Not worried about that in my case, just that it is more accurate than H4530 or H4831 with the 130s in my rifle.

Just got back from the range, trying out some 150 partitions. 57.0 of H4831SC gave a 1" three shot group at 2860fps (22" barrel,29 degrees). 57.5 bumped that to 2900 fps but the primers were looking too flat for me. I will need to load up some more at 57.0.

Mike

Me neither, thinking it'd be a pretty fine line to follow that one thru however?

That said, I have burned a lot of 22 in my .270's over the years. Lots of good powders for that good old round.

Dober

.035 growth is not much. I have them grow .100-.200, just keep seating the bullets out. As the lands thin(burning chamber is about 10"), accuracy gets here today and gone tomorrow.

Often changing to a semi point type of bullet restores accuracy for quite a while, the Nosler 160g Partiton is a great bullet for this application.

Also, as barrels get worn, often you have to bump the powder charge a litte to get back the same pressures that you were running when the barrel was new.

Bob, you don' just seat them out so you stay off the lands a predetermined amount (say your rifle likes .020" off so you keep seating them out)....That and bumping the charge up like Keith suggested...

For the 130's I prefer H4831sce but for 150's my new favorite is IMR7828ssc. I have never been able to get the 150's to 2900 in a 22" bbl using H4831. 7828 will do it.

That's true RinB, 7828 is very good in the .270. It and the 140 Horn has done well for me over the years.

I've probably burned more 7828 than anything else in my life. Course using it in the Mashburn sure helps to go thru the cans.

Dober

The other side of all this is, as somebody wise once pointed out, "They make new barrels every week."

And thx for that eh...

Dober

that great gun