When my rifles were new, I measured bullet ogive to land contact before developping handloads. Today, each of these rifles has shot "X"many rounds and I took new readings to assess throat erosion. Apart from my Ruger .22-250 (see former posts), all showed wear compatible with the amount they were shot, if it wasn't for this surprise.

I have two .300 Win Mag :

- a Rem Sendero SS, shot 313 x and the lands eroded for 1,15 mm (.045") ;
- a Blaser R93 CM steel, shot 331 x and I got the same readings as when new !?!

Like many, I have been brought to believe that SS resists erosion better than CM. OTOH, I'm amazed to find no discernible wear in the R93 bbl.

Any comment ?

NB. :
1. all data are the average of 5 consecutive readings, taken with a Stoney Point OAL gauge ;
2. both rifles pet loads make use of same bullets / powder, except for minor charge and COL adjustments. Also their primer liking differs (CCI 250 vs. WLRM).

I did a lot of gopher/prairie dog shooting in my youth and had two 22-250 rifles built with the same make barrels and the gunsmith used the same reamer to chamber them. One shot best with the bullets just off the lands and the other shot best with .025 jump into the lands, this rifle showed startlingly more throat wear than the other and while I generally shot one till it got warm and went to the other and traded back as it got warm I generally traded rifles at the 15 round mark. It also fouled more.

[ 03-08-2003, 19:30: Message edited by: rickt300 ]

Just a thought, and for those who are tracking throat errosion using these gauges, in order to obtain the most accurate data possible, you have to use the "exact" bullet that was used to obtain your initial measurements. There can be enough of a difference between the same type bullets, to give erroneous results.

Malm

You're compairing German steel to American steel.

Andre, it is always better to put 25 to 30 rounds through a new barrel before taking your first reading as this will clean up any tool marks or burrs. I have 400 rounds through my Shilen 22-250 and throat has not moved since round 25.

Doug, well Belgian steel it is, actually. Word got to me that Blaser bought its hunting barrel blanks at Delcour (a old and reputed custom bbl. maker in Li�ge... until they were taken over by FN-Browning, a few years ago) and got the target/LRS from Lothar Walther.

TBS, I tend to agree, new chambering burrs seem logical in that 300+ rounds of .300 Mag must in one way or another leave a trace.

I have, over the years, seen several cases of accelerated barrel wear in SS barrels from a number of makers. These were barrels that were visbly worn in the throat after less than 500 rds in barrel friendly chamberings (6PPC, 6BR, 308). I have never seen this in a chromoly barrel. FWIW. Regards, Bill.