i noticed while working up loads for my 8mm-06 mauser 98 and my 300 win mag howa that the group sizes tightened up and the velocity devation got smaller as i shot more. i thought accuracy should have been best from a clean barrel but seems to improve to its best after 12 to 15 shots. i haven't shot enough with either rifle to see if it starts to drop off at some point. when i say the barrels are clean i mean clean, no copper, no powder fouling, and no oil.

has anyone else observed this? does it vary from gun to gun?

It varies very much from gun to gun.I have owned rifles that did shoot better after a few rounds were fired but my present rifles shoot equally well and to the same point of impact out of a clean barrel.I have also owned rifles where the accuracy dropped off in as few as 12 to 15 rounds.

I have a sako in a 30-378 that seems to like the xlc bullet really well. Haven't tried the tsx yet. BUT, it shoots best after about 12-15 rounds also. Now lets see...that is one fun caliber to have to put that many fouling rounds through before a hunt..especially if it's warmer that 60 degrees out.
On the same topic (sort of) I;ve been taking a boresnake to the range with me. About every 15-20 roundsI do a pass with the snake. I swear it keeps the barrel clean enough to test ammo for hours. It also seems to make cleaning at home much easier than it used to be.

I have barrels that are both ways,..so it all depends on the individual barrel itself. This includes match grade stainless barrels as well.

And are you all going to be able to outshoot the difference in the field, puffing,excited,rushed, unknown range, unknown wind effect. And the last time I got a good group, my mate says, "yep, seems like one can hook shots into the bull as well as out."
JL.

Hey Lobo, I agree with all the above including "yep, seems like one can hook shots into the bull as well as out", which I refer to as Random Group Dispersion (but isn't as funny with a buddy ).

I prefer to hunt with a spotlessly clean barrel which has been lightly lubed and then wiped dry with a couple of Paper Patches to remove any excess. This still leaves a small film of the lube present to protect the Bore from the elements. And over all the years I've been hunting, I really don't remember taking a 3rd shot at Game. Even two shots can be counted on one hand for five decades of hunting.

I just don't hunt with a "fouled" barrel as some folks do, so I clean the barrel and relube quite often at the Range. I will go normally 6-9 shots and then clean the barrel while Developing Loads.

But, once the Load is determined, I'll typically go to 2-shot groups and really prefer cumulative 1-shot groups. That requires cleaning and lubing after every shot, but it is the condition the barrel will be in while I'm hunting, so that is the condition I want it in when practicing.

Best of luck to you.

For me it has varied depending on the rifle more than anything. My 7mm RM in a Win 70 really shoots the Barnes XLC's AFTER it's "dirty". And to be honest, I have yet to find a better shooting load with any other bullets, whether the bbl is clean or dirty!

I don't notice that much of a difference in other rifles. I'm not that picky but it was obvious in the 7mag. I do have a bbl that shoots when clean but starts to wander badly as it heats up and gets dirty.

It does seem they each have their own personalities. Nate