243 gone wild

[jbs606]

I have a 243 Howa in a heavey barrel. This gun was shooting great for the past 6 mouths. Over the weekend I took it to the range and my groups went from 1" or less groups to 3". I have been loading them the same all this time. But from time to time I will try another weight bullet. For the load I thought I had worked out for this gun was 87 gr. Hornady with IMR 4064 36 grains.
Any idea why my group has gotten so much bigger.
Jbs

 

[hoghunting]

Did you check the action screws to see if they were tight? How about the rings and base? You can't really check the base screws without removing the scope, so push against the scope and check for any movement.

Did you do a thorough job of cleaning after your last range session? Many barrels shoot better with a little fouling.

Do you have any of your proven loads that you can shoot so you can eliminate the possibility of your last reloads?

 

[jbs606]

Hog
Yes I did check the scope, and I clean the gun the same each time at the range when I am done. As for my loads I have a box of 50 rounds of proven loads that I tried that day and they were out as well. When I was back at the house I recheck my seating depth. This was not the same as it was when I frist started shooting this gun. It was a lot diffrent from my frist measurement I had. Could my barrle be shot out after only 350 round fired thru it?
The 87 gr bullet just touch the lands at 2.735 and I was seating the bullet at 2.695. This seating gave me great groups. But when I recheck the seating it was 2.793. I am not sure if I could have check it wrong the first time or if this is right. I check it three diffrent way's this time and came up with the same with-in .005.

When I got into reloading I didnt have all the tools I have now to check thing out with as I do now, but the way I check it the first time is one of the ways I check it this time.

Need help.
Jbs

 

[jbs606]

Hog
Yes I did check the scope, and I clean the gun the same each time at the range when I am done. As for my loads I have a box of 50 rounds of proven loads that I tried that day and they were out as well. When I was back at the house I recheck my seating depth. This was not the same as it was when I frist started shooting this gun. It was a lot diffrent from my frist measurement I had. Could my barrle be shot out after only 350 round fired thru it?
The 87 gr bullet just touch the lands at 2.735 and I was seating the bullet at 2.695. This seating gave me great groups. But when I recheck the seating it was 2.793. I am not sure if I could have check it wrong the first time or if this is right. I check it three diffrent way's this time and came up with the same with-in .005.

When I got into reloading I didnt have all the tools I have now to check thing out with as I do now, but the way I check it the first time is one of the ways I check it this time.

Need help.
Jbs

 

[Serendipity]

Put some Magic Marker or Sharpie ink on a bullet and chamber a round 2C if the bullet is hard into the lands. Could be the problem, and that'd be pretty simple to fix.

When you clean after each session, how much cleaning do you do? Do you use Sweet's or something like Sweet's to detect if there's copper fouling present?

 

[JackOfAllTradesMasterAtNone]

Your seating depth mesurements are confusing me. Are these the measurements out of the box, or are these some you've pulled out of the magazine after firing one or two? Could your bullets be affected from recoil and unseating a bit when in the magazine when you fire a round?

Two things come to mind. Improper seating depth according to your notes from proven rounds -Adjust seating die.

Different design bullet, but same brand/weight. This could affect seating depth.

Re-measure chamber/lands length.

Yes, -what Serindipity said.

I'd re-seat some to the dimmensions you have in your notes. Fire them as single shot. No, your barrel should not be shot out this young. The aformentioned notes about scope mounting and such.. Have you been shooting a high power rifle and now are "flinching" at the recoil of the little .243? Have you thought of letting someone else shoot your rifle to be sure it's the rifle and not you?

-I did this for a friend once and to my pleasure, I got to tell him that his rifle and loads were just fine. (awesome in fact)

-Steve

 

[jbs606]

Jack
On the day I was shooting this gun, I was also shooting a 308 Savage. The goup was close as it alway is with-in one inch at 100 yard. On all my bolt guns I always load one bullet at a time when I am shooting it.
My overall measurement were out of box. I do trim case's when needed. They dont need to be much because I neck size only on all my bolt guns.
As for my cleaning I use this foam stuff, cant think of the name of it right off hand. Then I use krol oil after I am done with foam stuff.
But next time I go to the range I will have some one other than me shoot my gun like you said and see if it could be me.
Jbs

 

[hoghunting]

jbs,
Let us know what happens after your next range session.

I don't think 350 rounds in a 243 would have hurt the barrel at all. Are you using a bore guide and stainless, carbon fiber, or coated cleaning rod? Highly recommend both to prevent abrasion from cleaning.

 

[Matt-man]

My initial reaction: That barrel's not getting cleaned well enough. 350 rounds isn't enough to burn it out, but it's sure enough to get it dirty.

As for my cleaning I use this foam stuff, cant think of the name of it right off hand. Then I use krol oil after I am done with foam stuff.

How long do you let it sit in the bore? I use stuff like that too, and if I don't let it sit in the bore and work on the fouling for a good long time it doesn't get the barrel clean. So now I leave it overnight.

If in doubt, see if you can find someone who has a borescope and have a look. It'll be obvious whether the barrel is dirty or not. If you are wondering about the condition of the throat, the borescope will show you that too.

 

[jbs606]

Thanks All
I took my gun down from stock and left the scope alone but did check and see if it was on good. Clean bore overnight.
Had some loads that I have had for some time. Went to the range, the gun shot great. Dont know what I done or what was wrong, but it is shooting good now.
My first 5 shot group was 1.5 at 100, the 2nd 5 shot group was 1.00 at 100 yards. Then the 3rd it was back .5 at 100 yards. It seemed that the warmer the barrle got the better it shot.
Thanks to all for the help
James

 

[Hutch]

Coulda been the bedding. If it goes south again, try the old dollar bill trick and make sure the stock isn't contacting the barrel.

 

[hoghunting]

jbs,
Glad everything worked out. It's a great feeling when you know your gun is working perfectly again. Enjoy the 243.