Shot barrel out in 220 rounds?

27 February 2002, 23:03

I measured OAL on my new .22-250 Weatherby SVM using Stoney Point gage. Using 52 gr. Matchking HPBT bullets I got 1.975", ogive to base of cartridge (average of five measurements.)

220 rounds of factory ammo later, I remeasured using same Matchkings. Now the OAL is 2.087". This says the leade opened up 0.112" in 220 rounds. How can it be that much? I know 22-250 is supposed to be a barrel burner, but wow! There is barely sufficient grip on bullet when it is placed back 0.010 - 0.020" from lands.

What happens in another 220 rounds? Will I be chasing the rifling right out the muzzle?? I followed accepted barrel break-in procedures and at no time did the barrel get beyond lukewarm to the hand touch.

27 February 2002, 23:30

<gone hunting>

send the rifle back to Weatherby!

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Death Before Dishonor

28 February 2002, 01:41

<Gary Rihn>

I have a buddy who had essentially the same thing happen on him. He noticed a big increase over the first few hundred rounds, now it is practically unchanged from that. It seemed to have hit a certain point rather quickly, then stopped. Strange.

28 February 2002, 04:36

Hot Core

Hey Zircon, I know there are a whole bunch of folks who swear by that Stoney Point tool, but I'm not one of them.

I have a buddy who "tried" to give me one after becoming frustrated with it giving erratic dimensions. So I tried it, also found it to be erratic and gave it back to him.

That said, you mentioned taking an Average of 5 measurements, and I'd think that should give you a fairly decent chance of getting it to work properly.

But, you may still be seeing "some" variation in the Stoney Point tool.

Or, if you used a "different bullet" from the same box, the Ogive on it might be slightly different.

Also sounds like you did not "burn the barrel" by shooting it when it was too hot.

As a final thought, sometimes having the bullets real close to the Lands just isn't necessary. One of my rifles has a 0.268"(yes over 1/4") jump to the Lands with a specific bullet and it has put 9 of those 35cal bullets totally inside a 1" square over the course of a day. Looking at that target, it is in the 5s for those 9 shots.

So, don't give up on yor rifle too quickly. Try various seating depths and it might even shoot better for you.

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Good hunting and clean 1-shot kills, Hot Core

28 February 2002, 05:47

Robgunbuilder

I've seen many barrels do similar things. I suggest you make a cerrosafe chamber cast and see exactly what is going on. look for erosion at the throat. If present it will be obvious. On a new barrel I make a cast and then a second after about 300-450 rounds. Often particularily in hot calibers, 257 WBY, .17 Rem, there will be obvious throat erosion.In nearly all cases, however, simply seating the bullet out a lil more will restore the accuracy and precision. The 22-250 is not considered a barrel burner and you should get 3000-4000 rounds through one before they start shooting >1 moa. Don't give up yet!-Rob

28 February 2002, 07:59

John Frazer

quote:
Originally posted by Hot Core:
Hey Zircon, I know there are a whole bunch of folks who swear by that Stoney Point tool, but I'm not one of them.
I have a buddy who "tried" to give me one after becoming frustrated with it giving erratic dimensions. So I tried it, also found it to be erratic and gave it back to him.

I found it deathly hard to use and inconsistent with the rifle just laying in my lap -- but very easy to use and very consistent once I started following the instruction sheet to the letter.

I.e., put the rifle in a cleaning cradle or similar rest, and push back against the bullet with a dowel inserted through the muzzle. This improves your feel for when the bullet touches the rifling -- it really does feel as if it's sticking.

Also, after you take out the tool, you really must measure the OAL with the Stoney Point comparator and the proper insert on your caliper, to eliminate bum readings on squashed bullet noses.

I do this once each with three bullets from the lot I'm using. Normally I will get two bullets exactly the same and one a thousandth or two off and I go with the best two out of three.

John

28 February 2002, 08:19

Hot Core

quote:
Originally posted by John Frazer:
...but very easy to use and very consistent once I started following the instruction sheet to the letter.

Aaaah haaa, there is an instruction sheet???

And you "read it"?!?!?!?!

Hey John, Sounds like a great idea to me. ;^)

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Good hunting and clean 1-shot kills, Hot Core

28 February 2002, 12:52

Zircon

Thanks, guys. I'll try the cerro cast. I'm reasonably certain the Stoney Point gage is working because when I assemble dummy rounds with bullet set to seat just at the lands, I can easily chamber the round, and I just see where the faintest of marks is on the ogive from the lands. Also, remeasuring the round after unchambering shows that it has not collapsed or changed OAL.

Also, I'll keep shooting it, and working with different seating depths. This is primarily a working varmint rifle and, while the accuracy stuff is fun, the real criteria is "minute of sage rat" accuracy. Early testing showed it will shoot in the 2's and 3's, but don't have accurate results now with the errosion.

28 February 2002, 12:54

<bigcountry>

Instructions. Somebody actually read those. Only thing I should have read the instructions on is my gas grill. that hissing with fire shootin thru the bottom was enough to make anyone break open a bunch of words.

Good tip, I never read those dad gone things either. I didn't think the dow thing was worth while. I will give it a try.

02 March 2002, 13:52

John Frazer

quote:
Originally posted by bigcountry:

Good tip, I never read those dad gone things either. I didn't think the dow thing was worth while. I will give it a try.

I do have to confess that I had exactly the same instinct at first ... only read the instructions out of sheer frustration. D'oh!