Barrel shooting better warm then cold

[Firemedic710]

Recently I put together a lightweight 300 wsm. Carbon 6 barrel, xlr chassis, defiance action, Nightforce scope. Finally got around to shooting it and have found accuracy to be an issue. I have 8 different factory loads. All shot from bags on the bench no wind with 5 min between shots. It shot 1 to 1.75 inches at 100 yards. Not horrible but was hoping for better. Now the funny thing is I shot a quick 3 shot group and the to my surprise it was .6 inches. I repeated this with all the loads. Every load was consistently smaller with a warm barrel than a cold. Barrel has 81 rounds down it.
The biggest offenders of this phenomenon were the better ammo I was hoping to use such as Barnes, Hornady and nosler.

Tomorrow I’m im going to retorque the action screws and try to get back to range. Does anyone have any other suggestions?

 

[Slugz]

-I'd say first is to see if this is repeatable.

 

[eric1115]

-I'd say first is to see if this repeatable.

Agree. A 3 round group tells very little. I've shot more 10 round groups this year than I have ever before and it has really changed the way I view rifle precision. 1.1-1.2 MOA is good. Sub MOA is very good. There's always at least one set of 3 (or sometimes 5) in a 1.2 MOA 10 round group that makes a sub .5 group (Sometimes a lot smaller). If they happen to be the first 3 of the group, it lies to you.

I can't deny it's something of a siren song, but resist the urge to chase the small size, small round count groups. There's nothing but frustration and lies that way. You'll have some great groups, some bad groups (I probably pulled that shot), but if you're paying attention you'll see that those great 3 round groups are rarely centered at POA. So add up all the tiny groups and what do you have? 1.2 MOA probably.

 

[KenLee]

You are thinking too much when taking your time

 

[Dmoua]

Cold shooter.

 

[Firemedic710]

Agree. A 3 round group tells very little. I've shot more 10 round groups this year than I have ever before and it has really changed the way I view rifle precision. 1.1-1.2 MOA is good. Sub MOA is very good. There's always at least one set of 3 (or sometimes 5) in a 1.2 MOA 10 round group that makes a sub .5 group (Sometimes a lot smaller). If they happen to be the first 3 of the group, it lies to you.

I can't deny it's something of a siren song, but resist the urge to chase the small size, small round count groups. There's nothing but frustration and lies that way. You'll have some great groups, some bad groups (I probably pulled that shot), but if you're paying attention you'll see that those great 3 round groups are rarely centered at POA. So add up all the tiny groups and what do you have? 1.2 MOA probably.

I understand what you’re saying, and I see the current trend of large groups. I don’t chase small groups, I chase consistency.

I repeated this scenario 6 times with the 3 loads I’m hoping to use. Every time the cold barrel group was 2 to 3 times the size of the hot barrel. With a poi shift 1 inch to the right.

I don’t want to boast but for those thinking it’s me it’s not. I’m a pretty solid shooter, taken a fundamentals class with frank and mark from snipershide. I shoot a lot with my neighbor that was an Army Ranger sniper and I’m on par with his skill set. Something just doesn’t seem right.

 

[eric1115]

I understand what you’re saying, and I see the current trend of large groups. I don’t chase small groups, I chase consistency.

I repeated this scenario 6 times with the 3 loads I’m hoping to use. Every time the cold barrel group was 2 to 3 times the size of the hot barrel. With a poi shift 1 inch to the right.

I don’t want to boast but for those thinking it’s me it’s not. I’m a pretty solid shooter, taken a fundamentals class with frank and mark from snipershide. I shoot a lot with my neighbor that was an Army Ranger sniper and I’m on par with his skill set. Something just doesn’t seem right.

If you overlay multiple groups do they have a consistent POI?

I'd be looking at free float and bedding/action screws torque, and if there's nothing goofy there I'd be contacting barrel manufacturer.

 

[Firemedic710]

I’ll attach pictures 1st is the eldx, 2nd nosler accubond, 3rd Barnes ttxx. This barreled action is in a xlr chassis.

The other ammo Remington tipped corelokt Winchester deer hunter xp and Winchester copper impact shot moa or better cold and down to .4 hot.

If I weren’t in Alaska I’d happily hunt with those rounds but I would really prefer Barnes or nosler.

 

[wind gypsy]

Cold shooter.

This was my first thought as well.

It is easier to shoot tight when you shoot a group without breaking position. When you rebuild your position between every shot it's much easier to do so inconsistently and thus varying shooter input on the gun, eye position/parallax, and recoil management can result in POI shift. Recoil magnifies it.

 

[waspocrew]

More recently, I’ve moved away from taking breaks between shots and I haven’t really noticed a difference in groups opening up. My time at the range has definitely become more efficient as well.

Do you reload by chance? Factory ammo (even premium) can be a gamble.

 

[ResearchinStuff]

Aside from cold shooter, it could also be the Barnes. I've seen a couple barrels that did not like shooting barnes after cup and core, or vice versa, without cleaning. One of a few reasons I don't shoot barnes any more.

 

[TaperPin]

What an interesting problem - it’s not very often it’s so dramatic and repeatable.

I’d swap the scope. My failed scope with a loose lens would shoot great when the lens was in one place, but the lens would rattle around almost making a specific pattern depending on where the lens was resting.

If you have a loose lens I could see it in a random orientation at the start of shooting, and settling in after a few shots. A quick scope swap would test for this.

 

[TaperPin]

If you’re not cleaning the barrel and live in a humid area, I wonder if the fouling fuzzes up as the rifle sits and has time to absorb a little moisture and is smoothed out with a few shots. I’ve seen borescope images of a guy who had a “flap” of copper fouling near the muzzle that was attached at the rear, but was loose and allowed solvents to get under it, but not actually remove the weird flap.

If you have a can, maybe more chunks of carbon fall back into the muzzle while it’s relatively cold?

 

[Firemedic710]

Spent all day at the range yesterday. Turns out this barreled action is very sensitive to the torque on the action bolts. I was able to tune it essentially, I can now shoot the accubonds (that’s what I had most on hand) hot and cold sub moa. I have 3 other barreled actions I drop in this xlr chassis that I simply snug and they shoot phenomenal.