.243 throat erosion?

[750k2]

What kind of erosion do you have?
Round count/erosion?
Hot or light loads?
Did you ever run her hot?

Went doggin for the first time this year - I couldn't help
myself I had to toast my bbl a little. Or maybe alot:nono:

 

[fdshuster]

750k2: Burned out a Douglas chrome moly at 1400 rds. A Shilen stainless followed, noticed accuracy falling off at around 1150 rds., more copper fouling, etc. and it also was done at 1450. Both barrels as seen with my 'Hawkeye' borescope were heavily fire-cracked, throats greatly lengthened. Standard load for both was 34 to 37 grs. of IMR 3031 with 75 gr. Sierra #1510 h.p. flat base, all fired single shot. I am able to quote exact # of rounds fired since I keep a log book for each of my rifles.

 

[AckleymanII]

Here is the fly in the ointment: throats vary in length from a brand new rifle, to a gunsmith's chamber specs.

The longer the throat is when the barrel is new, the quicker the barrel 'burns out'. Reason being is that a bullet will only jump so far before it starts in the barrel crooked, shaving off one side of the bullet.

I have had barrels with very fire cracked bores that shot like a house a fire but the bullets were still engaging the lands as loaded rounds.

There is a certain amount of bullet jump that will work, each barrel is different along with each bullet design.

When I was in the heat of the dog wars, I would put 1800 hard rounds through a 243 AI that started off with zero freebore, and the leade would grow .075-.100 depending on how rich the target enviroments were that I shot in. Typically, I would dump out a box of 50 rounds and fire as fast as I could load and acquire targets...those were the good old days. I was shooting a load of 48.5g of Win 760 with a 70g bullet at 3850 through a 243AI.

I would set back the barrel .750-2.0 inches depending on the wear. We would get 3 chambers out of a 29-30inch unturned blank as 243 AI before the barrel was too short, then became a 6BR at 24 inches for use on jacks.

So, this does not answer your question directly, but may give you some insight on your next barrel. The Max heavy varmint barrel has 6' of straight on the shank and you can set back the barrel at least twice on this barrel taper, as long as you start off with zero freebore.

Good luck

 

[750k2]

I've lost .060 in 700rds
Have a stub of bbl that was made as a seating gauge when I
rebarreled. Going off of that.
Varmint contour and figure I'll get one set-back
Varget and 65 Bergers and Barts @ 3600
Was just curious if my results were out of line.
I figure one more dog trip and then set back for one more
and then it's another Krieger for me.
There is no way I can control myself in this doggin stuff.
I have no problem with having to buy bbl's.

 

[AckleymanII]

holy cow, Varget must be rough on barrels. Ever done any sand blasting? The coarser the sand the rougher the surface finish you get.

I got a lot better barrel life with win 760 than you are getting with Varget.

 

[750k2]

When you set-back how much has your throat eroded?
Mine still does not copper and shoots good.
Maybe I'll burn some slower stuff next go round.
They always make more bbls so I'll see how long she goes.

 

[mikecr]

The 243 isn't for grouping. It's a hunting cartridge.
The only grouping you should be doing with it, is cold barrel grouping, for cold barrel shooting.

I'll try to attach a small spreadsheet here so that you can get a feel for this. I've pre-loaded Franks load above. You notice using it, that dropping shot rate to 30sec/shot,for grouping) causes a resultant barrel life which is in-line with Franks experience. I've posted the file here before,a long time ago).
Still holds true I guess..

 

[watercam]

Was periodic JB Bore Brite and/or brush and patch lapping part of your routine? I go the JB route every 500 rds.,40 passes) and lap every 1000,20 passes w/ 600 grit). Barrels come back to life nicely. Has worked with a Lilja .243, Shilen .30-06, factory Ruger .257 Roberts, Winchester 52C rimfire.

 

[750k2]

Still plenty of life in her, I use this for PD's and the now and then water bottle
and golf ball games my buddies play.
I'm still under 1/2' and can still get my 65's out to the lands.
When they wont reach I'll go to something a little heavier.
Was just looking for others measurements and what they have had
for erosion.
If I want a bbl to last I wont count on a 243 I'll use one of my little
guns - but will always take at least one 243 along because it is
real nice when the wind is up and range is on the long side.
Yes I use JB when ever the carbon ring shows up - I'll try the
lapping if groups ever open up.