My .243 has about 650 rounds down the barrel and would give really good results with many different bullets and/or powders. However lately it has gone all wonky at any range above 100yds. My go to load is 87gr Vmax with H100V powder at 39.6grs and will group dime size hole at 100yds. and just over 1 inch at 200yds and under 2 inches at 300. Yesterday and today as well best I could get at 200yds was a 4.5 inch group! I have noticed that this has been getting worse for about the last month or so and have cleaned the barrel with several cleaners and copper removers with no improvement. Could the barrel be getting at the end of it life span? Oh, Winchester M70 stainless light barrel 24 inch.
What to look for when a rifle will no longer group.
- Thread starter Lefty Trigger
- Start date
Check action screws , scope base screws , scope ring screws . Check bolt handle , trigger , and barrel clearance . As noted above clean if you think it's clean buy a Borescope, it's the best cleaning gear to have . It'll pick up flaws such as possible rust , I know I know ,it's stainless ! I've seen more rusted stainless than chrome moly in the last 20 yrs . It's natural to assume you can clean it later , only to find some pitting in the bore .
Has anything , ANYTHING, changed ? Powder lots , bullet lots , primer , cases, bullet lots ?
Has anything , ANYTHING, changed ? Powder lots , bullet lots , primer , cases, bullet lots ?
I'll catch hell but, the 243 can burn the lands quickly. If you seated the Vmax slightly into the lands, you might be jumping now. Borescoping is very important as you will likely see a carbon ring in the neck portion of your chamber, plus you can see the condition of you lands. All other suggestions are good.
Powder, same (tried several brands with same results). Bullets are same lot. Primers are the same CCI 200. Brass is the same. I have scrubbed and scrubbed the bore with several cleaners and copper removers. I even purchased a "foam bore cleaner" that you cork one end and fill the bore and let it soak. Going to try that. I really need a bore scope or to find somebody close that has one to look and see if I'm chasing a worn barrel. It most likely has 600 to 700 rounds through it. I was told when I bought it that the 243 was a "overbore" and would eat barrels.
Not in 600 rounds . At least not that I've seen . Sorry no coffee yet ,
What about stock , scope and rings , still all the same and checked for tightness . Make sure the stock and scope screws aren't too long and touch either the barrel shank , bolt or ?
shortstroke the throat with a parker hale jag with a.patch wrapped.around it soaked in boretech C4 and coated with losso. buy a lyman borecam.
check all scope and base mounting screws for proper torque. also the action screws.
if it still won't shoot i would try a.different scope.
WyleWD
Silver $$ Contributor
Do you have, or anyone close to you have a borescope that you could check the barrel's condition, if so, that is the first place to start. If it's clean and no issues there then check for loose screws on the scope mounts, change to a proven good scope if that is an option, and of course check the tension on your action screws. I had a 243 light weight barrel that was beyond toast in under 800 rounds. JME. WD
hogpatrol
Gold $$ Contributor
Any high volume shooting? Was it used for prairie dogs? What scope brand and model?
There have been times I have shot 5 rounds as quick as I could chamber them but that is very few. No hunting strictly a bench gun, kind of a trainer for distance shooting. Scope is Burris XTR II F-class and stock is Aluminum bedded Choate varmint.
I just went through this with my rifle as well. Groups fell apart after shooting well. The fellas here gave me some great help.
I think what solved it for me was the JB bore cleaner and new bore brushes. I did the copper solvents and the foambore several time then went to the JB with a new brush. The black stuff that came out with the JB was incredible, even after getting clean patches with the other cleaners. If you have a carbon ring built up right in front of your chamber the JB is the best to get it out. Bore brushes wear our in about 100 strokes, new brushes can really make a difference.
Next check your action screws, I found out my action screws needed a lot more torque than I was giving them.
Last I would say seating depth, with the fast burning 243 the length to the lands may be starting to grow and causing more bullet jump.
Good luck, problem solving takes a bit of work but its worth the return in accuracy.
JB bore cleaner on sale
https://www.brownells.com/gun-clean...mbedding-bore-cleaning-compound-prod1160.aspx
I think what solved it for me was the JB bore cleaner and new bore brushes. I did the copper solvents and the foambore several time then went to the JB with a new brush. The black stuff that came out with the JB was incredible, even after getting clean patches with the other cleaners. If you have a carbon ring built up right in front of your chamber the JB is the best to get it out. Bore brushes wear our in about 100 strokes, new brushes can really make a difference.
Next check your action screws, I found out my action screws needed a lot more torque than I was giving them.
Last I would say seating depth, with the fast burning 243 the length to the lands may be starting to grow and causing more bullet jump.
Good luck, problem solving takes a bit of work but its worth the return in accuracy.
JB bore cleaner on sale
https://www.brownells.com/gun-clean...mbedding-bore-cleaning-compound-prod1160.aspx
So can changes in us ! Eyes change , glasses change , endurance changes .
I've been shooting the 243 since the late 60's and have own various brands. I would be stunned if you burned the barrel after only 650 rounds.
- All good suggestions by other posters.
- If you're dialing up and down a lot on your scope then I would try another scope just to rule out a scope malfunction.
- I would also try the Bore Tech C4 carbon remover w/ a bronze brush - this stuff really works.
- All good suggestions by other posters.
- If you're dialing up and down a lot on your scope then I would try another scope just to rule out a scope malfunction.
- I would also try the Bore Tech C4 carbon remover w/ a bronze brush - this stuff really works.
Whenever I have a rifle where groups open up drasticly the very first thing I do is check the scope bases. I don't use JB paste, I ruined a barrel with it by using it to much.
For cleaning new brushes usually make a difference and I use Sweets to clean the bores. Powerful stuff, but don't leave it in the bore. Use it and follow up with Hoppes and oil.
For cleaning new brushes usually make a difference and I use Sweets to clean the bores. Powerful stuff, but don't leave it in the bore. Use it and follow up with Hoppes and oil.
Dusty Stevens
Shiner
Tell us about ruining a barrel with jb- what method did you use to ruin it or did you just hear about this? I have used tons of it as have every br shooter that shoots and i have yet to see or hear of a barrel damaged by jb- and thats a battleship load of finely lapped custom barrels. I do hear this every once in a while but have never actually seen it and the person that brings it up usually hasnt either.
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