Groups out of a carbon barrel

[Dirtdevil]

I posted awhile back on load development on a carbon barrel. I was planning on sending the rifle back to the manufacturer tomorrow. So today I took it out one more time before I sent it in Was planning on sending a target with it Well guess what. Shot 3 groups under .75. Here's my issue. If you fire a shot let the barrel cool 5-10 minutes fire another let it cool fire another it's a 1.5-2 in group. If you just send them all 3 back to back it shoots great. It also prints same point of impact on target. Point being I guess my rifle is fine But I'm sure lost on why it won't group on a cooler barrel. Is that common. Have you guys had this happen

 

[matt_3479]

Well in general a lot of barrels and shooters for that matter have cold bore shifts. Meaning a cold barrel first round tends to be slightly different poi then following rounds.

 

[FireFlyFishing]

How many rounds through the pipe? It may need to stabilize with more shooting.

 

[Muddybuddy]

I posted awhile back on load development on a carbon barrel. I was planning on sending the rifle back to the manufacturer tomorrow. So today I took it out one more time before I sent it in Was planning on sending a target with it Well guess what. Shot 3 groups under .75. Here's my issue. If you fire a shot let the barrel cool 5-10 minutes fire another let it cool fire another it's a 1.5-2 in group. If you just send them all 3 back to back it shoots great. It also prints same point of impact on target. Point being I guess my rifle is fine But I'm sure lost on why it won't group on a cooler barrel. Is that common. Have you guys had this happen

That doesn't make sense. Shoot bigger groups.

If your first shot is a cold bore then the next two are a hot barrel, why would that group but 3 cold bores won't. Assuming I understand you right the 1 cold bore has the same POI as the 2 hot bores but 2 more cold bores won't have the same POI as the first cold bore?

 

[Dirtdevil]

About 300 rounds on the gun Muddy buddy You are correct. The cool barrel groups are larger than the warm barrel groups point of impact stays consistent. Hot or cold. The cool barrel groups open up A head scratcher for me Just wondering if anyone else had seen this. I'm new to carbon barrels Could that be a factor

 

[MagnumManiac]

Many stock factory rifles show this pretence for first cold bore shot to be 'out' of the group.
I had one such REM 700 Sendero in 300WM that did this from day one.
Did bedding, torqued action screws and played with action screw torque to no avail. Took the barrel off in frustration and found very sloppy machining on both the action and barrel with the recoil lug uneven to boot.
Trued everything, replaced the recoil lug and pinned it in place, set the barrel back, re-chambered it and put it back together. It shot no differently, cold, warm or hot after this work, even with the stock barrel. I believe the canted recoil lug was the culprit.
Groups were excellent with that rifle and only improved slightly, but an improvement is still a positive. Barrel is gone now, but that action was used for a custom switch barrel.
I doubt the carbon barrel is the reason, but it could be…

Cheers.

 

[matt_3479]

About 300 rounds on the gun Muddy buddy You are correct. The cool barrel groups are larger than the warm barrel groups point of impact stays consistent. Hot or cold. The cool barrel groups open up A head scratcher for me Just wondering if anyone else had seen this. I'm new to carbon barrels Could that be a factor

I don't want to come off rude here but I would like you to try this same thing with another rifle. Firing 1 shot, breaking position and waiting 5-10 mins, firing 1 shot and repeating sounds more like the shooter then the rifle. If your cold bore has 0 poi shift from the next 2 rounds and that's consistent and repeats then every cold bore should form a group similar to a warm bore. Which brings me back to "cold shooter"

 

[Jeffrey Van Zandt]

I posted awhile back on load development on a carbon barrel. I was planning on sending the rifle back to the manufacturer tomorrow. So today I took it out one more time before I sent it in Was planning on sending a target with it Well guess what. Shot 3 groups under .75. Here's my issue. If you fire a shot let the barrel cool 5-10 minutes fire another let it cool fire another it's a 1.5-2 in group. If you just send them all 3 back to back it shoots great. It also prints same point of impact on target. Point being I guess my rifle is fine But I'm sure lost on why it won't group on a cooler barrel. Is that common. Have you guys had this happen

in most cases it is not a cold barrel but a cold shooter

 

[Lazy D]

Sounds like a SA 2020 Waypoint. I've recently sold 3 to some SOT officers, two are snipers. One rifle will shoot .5-1 MOA consistently the other two are much like you describe. I'm on the fence about BSF barrels. They are supposedly made with an air gap between the carbon fiber wrap and the actual barrel.
If yours is not a 2020 well,….just disregard my ramblings.

 

[Mikecr]

If you fire a shot let the barrel cool 5-10 minutes fire another let it cool fire another it's a 1.5-2 in group. If you just send them all 3 back to back it shoots great. It also prints same point of impact on target.

This is a brutal test which I discovered a long time ago -helps me.

I do a lot of cold bore accuracy testing (after full hot bore load development).
I do it at my worst range (200yds for some reason), and at a 10min/sht rate, because I discovered that this is always the worst rate.

When I CB develop I want to see my worst. I want to know up front whether the gun has any real cold bore hunting potential.
With this I've seen guns with excellent precision (hot bore grouping) that I would not consider CB accurate enough for hunting. Worst here was a Tubb T2k tube gun.
I have also seen guns that were terrible hot bore groupers, but VERY cold bore accurate. A Browning A-Bolt re-barreled to 6BR stood out in this regard.
Two guns I hold that shoot both equally: a Cooper and a custom BR gun I built.

Your wrapped barrel may be presenting what I seen with my tube gun. It had to be stable to shoot. No transients.
I could warm-up shoot a few, move over to a 600yd target and put 5 or 10 shoots into a 2" bull. No problem.
But if I then wait 10mins and fire another, it would miss the bull. Wait another 10mins and fire another, it would miss the bull again, with the missed shot close to prior missed shot. If I quick fire off another, this shot returns to the bull.
So the gun did what it was designed to do,, it was never a hunting gun (as I hoped it 'could be').

 

[Rick Richard]

Any gun that creates continual frustration for me goes down the road. I ain't fighting or compromising…life is too short.

 

[FireFlyFishing]

Any gun that creates continual frustration for me goes down the road. I ain't fighting or compromising…life is too short.

I hear ya. I'm dealing with this right now. I had a good shooter that has gone down hill. I'm starting to think it's now the scope that's gone funky on me. Took me awhile to get to that conclusion though….

 

[Huntnful]

I would stop trying to fully attribute it to the carbon barrel. It could just be a 1.5-2 MOA gun and you got lucky on a few 3 shot groups that landed .75". And now you're trying to correlate a bunch of stuff that isn't actually firmly proven well enough.

It could be bedding issues too.

Could be you getting up from the rifle 2 different times while it cools.

 

[skipglo]

That doesn't make sense. Shoot bigger groups.

If your first shot is a cold bore then the next two are a hot barrel, why would that group but 3 cold bores won't. Assuming I understand you right the 1 cold bore has the same POI as the 2 hot bores but 2 more cold bores won't have the same POI as the first cold bore?

.....wait... Who's on first?