Need help. POI shift

[Flyingbullseye]

I could use some help trying to find a solution to why I have significant POI change in my barrel. I currently have a .308 match barrel from a premium barrel maker that is causing me some frustration.

The barrel is a M24/40 type contour, 25in 10 twist. Round count is 700 to date.

The first 4-5 shots are all less than 0.5moa at 100yds however after the first 5 rounds things seem to go south. By the time I fire 15+ rounds the POI has shifted down and usually to the right about 2 inches and the groups open up to about 2+ moa. This is at 100, out to distance the hits on steel are inconsistent. I've checked all the usual suspects for shift and accuracy issues such as any type of fouling. The barrel doesn't show any copper using sweets, minimum carbon and the base, scope, action screws and barrel are solidly tightened down.

The warmer it gets the worse it gets. I don't first fast strings of shots but now that its summer it doesn't take long for the barrel to heat up. When I let it cool the first group is fine but quickly change after that.

What really gets weird is when I use my brake the groups look like I used a shot gun 10 out from the target.

I'm at a loss here and could use some help.

 

[agbm]

Give the barrel maker and the gunsmith a call. Many barrel maker's have a warrantys on their barrels.

 

[leadbullet]

make sure everything is tight on scope, base and action screws, also check if the barrel is free floated the whole length of the handguard.
cheers.

 

[Flyingbullseye]

Leadbullet, already did that as posted in the opening post. I did also check that its free floating its entire length. I'm hoping its not another bad barrel as I had one from a different maker that went bad on me fast less than a year ago.

 

[dragman]

I didn't see action mentioned. If the barrel is floated and scope bases etc are tight. I think it comes down to the action not being true or an issue in the bedding of the rifle. I think the bedding and action have just as much to do with this kind of problem as barrels do.

 

[DanSavage]

Ammo can do that too, reloaders can find a good forgiving node and stay at the low end of it, it should in theory keep same POI when the barrel gets hot.

 

[JGorski]

Kinda had the same issue last sunday at our 600yd BR match, shot this first group, then went down 1 click and got the other group 5 mins later, wind didn't seem to change, everything is tight, everything is match grade, yada yada.

 

[Brux]

OP posted 700 RDS down the tube,has the gun alway's done this?Was the other barrel you mentioned on the same action?

 

[rangeryo]

What kind of scope are you using?

Sent from my HTC6500LVW using Tapatalk

 

[steve123]

Check the torque on the barrel.

A few years ago my rifle was doing something similar. Due to a bad recoil lug the barrel loosened up over time. I bought my own action wrench and barrel vise, the first try ever taking a barrel off, braced myself for what I anticipated as a hard pull and it turned out the barrel only had about 5lbs of torque holding it on. Tightened it back up to 50lbs and was GTG.

 

[winxp_man]

Kinda had the same issue last sunday at our 600yd BR match, shot this first group, then went down 1 click and got the other group 5 mins later, wind didn't seem to change, everything is tight, everything is match grade, yada yada.

JGorski do you use a cant level system on the rifle? It would seem your accuracy is there but you just have a change in poi as if the rifle tipped to the other side. Another thing to remember is that at 100 you can maybe get away with cant but not at 600 where it gets magnified a bit more.


From what I'm understanding the Op is also having an accuracy issue not just a poi issue. Also before we get deeper into talk. I want to ask as has it done this from the beginning? I will say like stated above me. Bedding job maybe no don't right? Actions screws tightened correctly as in tighten the front hand tight then the back the torque the front (as in just side front) to spec then the back.

 

[JGorski]

JGorski do you use a cant level system on the rifle? It would seem your accuracy is there but you just have a change in poi as if the rifle tipped to the other side. Another thing to remember is that at 100 you can maybe get away with cant but not at 600 where it gets magnified a bit more.



From what I'm understanding the Op is also having an accuracy issue not just a poi issue. Also before we get deeper into talk. I want to ask as has it done this from the beginning? I will say like stated above me. Bedding job maybe no don't right? Actions screws tightened correctly as in tighten the front hand tight then the back the torque the front (as in just side front) to spec then the back.

I have a bubble level just like this on my other 6 Creed, and I use it, too, LOL. I'm pretty sure Chad did a great job bedding my rifle, not sure about the OP.

 

[Flyingbullseye]

Ok, I'm going to answer everyone's questions/help.

The action is a trued 700 in a manners mini chassis T4 stock and previously had a Rock Creek barrel.

No, with the rock it didn't do that but did give up the ghost fairly quick due to copper fouling that Rock said was due to a bad batch of barrels put out. I will give him credit that he sent me 2 barrels to cover the cost of the new one.

The new barrel is not a Rock and yes it appears to have always done this. The first couple of range days I didn't pay much attention to this as I was load developing.

Barrel is torqued to 100 ft/lbs, action torqued to manners specs. As is the base (EGW HD) and rings (seekins).

Scope is a S&B 3-20.

 

[dragman]

Can you post up pick of bedding?

 

[xringaccuracy]

Are you using handloads or factory ammo. I ask as some powders are temp sensitive and as the heat goes up the powder works differently. I know some match shooters keep their ammo in a igloo cooler (not iced lol) but it keeps it stable. Seems that the warmer a days temp gets the more erratic some powders become. Google it and you will have days of reading.

 

[Flyingbullseye]

Are you using handloads or factory ammo. I ask as some powders are temp sensitive and as the heat goes up the powder works differently. I know some match shooters keep their ammo in a igloo cooler (not iced lol) but it keeps it stable. Seems that the warmer a days temp gets the more erratic some powders become. Google it and you will have days of reading.

You know I always forget to add something to my post.

Handloads. I've used varget, 8208 XBR (both temp insensitive) and 4064, that one is. Doesn't matter.

I haven't used varget since I was load developing and have since sold it to a friend.

Both 8208 and 4064 show the same result, first 4-5 are accurate then POI shifts usually down and to the right but not always but always opens up. By the 3rd group of 5 I have no way of predicting where it will go relative to my aim. I am often good for a flyer now and then (shooter error) but there's a difference between and quarter inch off and minute of berm. Again, it gets even worse with a brake.

I was hoping to use this in a match but until this gets fixed no way.

 

[Wheres-Waldo]

Check the torque on the barrel.

A few years ago my rifle was doing something similar. Due to a bad recoil lug the barrel loosened up over time. I bought my own action wrench and barrel vise, the first try ever taking a barrel off, braced myself for what I anticipated as a hard pull and it turned out the barrel only had about 5lbs of torque holding it on. Tightened it back up to 50lbs and was GTG.

Typically the torque the bullet puts on the barrel/rifle will keep things tight (20 ftlbs or so I'd guess), depending on a plethora of factors of course.

A lot of guys proclaim not enough torque will cause POI shifts and fliers. I'll put a barrel on as tight as I can by hand (headspace measured at hand tight), by the time I have a few rounds through it its snug enough to require a wrench to remove.

Never had any POI issues due to barrel tightness.

Im curious as to weather the POI SHIFTS or walks out gradually? Does it return to "zero" once cool?

 

[-Claybuster-]

I really don't even understand why your still screwing around with the damn thing. Spend it back to whom ever built it and have them figure it out.

 

[Brux]

There could be several different issues to cause this.If your confident in your shooting capabilities I would start eliminating things one at a time,like try a different scope and see how that works.But with that being said it sounds to me like a heat treat issue on the barrel.I'm with Rick,send it back and let them figure it out.I would have done that before I sent 700 RDS down it.

 

[steve123]

Typically the torque the bullet puts on the barrel/rifle will keep things tight (20 ftlbs or so I'd guess), depending on a plethora of factors of course.

A lot of guys proclaim not enough torque will cause POI shifts and fliers. I'll put a barrel on as tight as I can by hand (headspace measured at hand tight), by the time I have a few rounds through it its snug enough to require a wrench to remove.

Never had any POI issues due to barrel tightness.

Im curious as to weather the POI SHIFTS or walks out gradually? Does it return to "zero" once cool?

Some gunsmith hadn't machined the radial lug correctly. The POI shifting was definitely the recoil lug and the barrel was barely holding on. Once torqued on the problem went away.

I had the same thing happen with a AR too - POI shifting. Except I cracked the barrel loose from the extension with my bare hands.

Pretty sure I have the unfortunate distinction of being the reining expert around here when it comes to loose barrels. I personally "now" believe that a barrel should be torqued on at least 50 lbs and more isn't a bad idea.

 

[Flyingbullseye]

I wanted to post an update now that things seem to have returned to normal. I talked to the smith/barrel maker and he gave me a long list of possibilities, many of which I've since forgotten. My shooting partner and I pulled the entire rifle apart to start checking off possibilities that we could do ourselves before I'd have to send it out.

We first noticed my timney trigger was coming in contact a little bit with the mini chassis so we busted out the dremel out and took care of that.

The next problem I never even noticed even though it was right in front of me but I don't know why I never saw it. The scope rings were too low and the erector housing was being forced into the base. All I was looking at was the objective clearance to the barrel and never checked the base to erector housing clearance. It left slight marks similar to ring marks on the bottom of the scope. Fixed that with taller rings.

Cleaned everything, put it all back to together and went to the range 3 times since. I am happy to report that 1 month later its shooting nice tight groups, kind of feel like I'm now cheating its shooting so well.

As for the smith and barrel maker it was Mark Chanlynn. Super nice and very knowledgeable guy and the work he did was superb, once I pulled the rifle apart his work became apparent. The barrel still shows no copper fouling at all, and little carbon fouling as well. Wish I bought one of his sooner.

Strange that 2 small things can make such a large difference but sometimes it does.

 

[Elite_KG]

To me this is a good example of why it is very hard to get anything more than suggestion(s) for possible issues in forum threads. Thread suggestions can and do help at times, but largely the "devil is in the details." I'm really glad you got it figured out as I know how frustrating it can be chasing down a issue.

 

[ryu_sekai]

I wanted to post an update now that things seem to have returned to normal. I talked to the smith/barrel maker and he gave me a long list of possibilities, many of which I've since forgotten. My shooting partner and I pulled the entire rifle apart to start checking off possibilities that we could do ourselves before I'd have to send it out.

We first noticed my timney trigger was coming in contact a little bit with the mini chassis so we busted out the dremel out and took care of that.

The next problem I never even noticed even though it was right in front of me but I don't know why I never saw it. The scope rings were too low and the erector housing was being forced into the base. All I was looking at was the objective clearance to the barrel and never checked the base to erector housing clearance. It left slight marks similar to ring marks on the bottom of the scope. Fixed that with taller rings.

Cleaned everything, put it all back to together and went to the range 3 times since. I am happy to report that 1 month later its shooting nice tight groups, kind of feel like I'm now cheating its shooting so well.

As for the smith and barrel maker it was Mark Chanlynn. Super nice and very knowledgeable guy and the work he did was superb, once I pulled the rifle apart his work became apparent. The barrel still shows no copper fouling at all, and little carbon fouling as well. Wish I bought one of his sooner.

Strange that 2 small things can make such a large difference but sometimes it does.

But why did it shoot fine the 1st 5 rds and bad the next. Seems like it would always shoot bad. If the issue was consistent. Glad to hear it's shooting well.