Cold to Warm Barrel POI shift... what is considered normal/acceptable.

[loudandproud]

I currently have a Savage 10FCP with a stock barrel. Rifle shoots very well overall but I do notice a point of impact shift as the barrel heats up.

The barrel seems to hold zero for about the first 5 shots in succession (every 30 seconds or so.)
After the first five shots, the barrel tends to climb about .15 mils from shot 6-10. After the barrel is good and warm, the barrel will then hold the .15 mil high POI. It seems to stop there.

Rumor has it a lot of these stock barrels are straightened and are not stress relieved.

A lot of you are running custom and top tier equipment. Do you find any considerable POI shift with this equipment? What do you all consider acceptable?

 

[Graham]

None.

 

[sib1948]

0.1-0.2 mil shift after the first shot with my DTA barrels.

 

[37841anarchy]

To my understanding it's fine as long as it's consistent each time.

 

[Dogtown]

0.1-0.2 mil shift after the first shot with my DTA barrels.

I concur, cold bore shot.

 

[nashlaw]

My Bartleins and Kriegers shift to the right and seem to stop after 5 shots or so.

My button - rifled tubes. . . . . . well, it gets interesting. Those Douglas barrels shoot wonderfully, but really take to walking when hot. I was really surprised this past week when I shot a 10 and 15 round group with my Meredith built .308 and shift was negligible and groups were tight.

 

[loudandproud]

So what im gathering here is that this amount of shift is relatively typical.

According to my data sheets... the poi shift has been consistant for the most part.

 

[loudandproud]

None.

What rig are you shooting? What caliber and barrel?

 

[TexasMade]

My krieger surgeon build doesn't have a shift ever. Even after you clean the bore

 

[M40_A1]

I adjust up .5 MOA for the first and maybe second shots from a cold, gilded bore or a fouled bore. That equates to your .15 mil. If my bore is clean down to steel, the drop on the first shot is significantly more, due to friction. Swabbing with graphite helps in that case to get me closer to the usual -.5 MOA cold bore impact.

 

[[email protected]]

I've never really seen a cold bore shot in either of my three customs (krieger and rock creek). However it shoots 1/2" low the first shot after I clean it, after that no mater how long it sits fouled it never moves. After around 10 shots in sucseccesion it will start to open up (300 WM)

 

[leadbullet]

My Kriegers and benchmarks barrel have zero shift cold bore or hot bore, clean or dirty, always on the mark.
You may have a bedding/ stock or an action tht needs squaring (best guess)
Cheers.

 

[Graham]

I am seeing a lot of cold bore answers, and cleaning answers, but the original question was about POI deviation as the barrel warms: From a cold barrel to a warm barrel after the first five shots. The answer is: None.

I am also seeing a lot of talk about barrel makers and rifling. But the OP doesn't yet know whether the problem is with his barrel or his rifle.

 

[sib1948]

Agree^^^^^^

 

[Graham]

Someone please ask the OP if his barrel is free-floating and whether his action is bedded.

 

[loudandproud]

None.

The action is in a b&c medalist with the aluminum bedding block, so no it is not "bedded" per say... the barrel is free floated. Plenty of clearance..

Someone please ask the OP if his barrel is free-floating and whether his action is bedded.

 

[Sterling Shooter]

I had a 264 Win Mag with forged sporter weight barrel which would "walk" rounds diagonally as the barrel heated up beginning with the first round from a cold clean bore. I also had a 6.5/284 with a heavy profile cut rifled barrel which I could not discern to be "walking" rounds from bore in any condition. I think most folks will have something between these extremes, whether shooting a cut, forged or button rifled barrel. We all hope for the best.

 

[shooter.dm]

I use a howa 1500 with a pac nor barrel in a b n c stock and I have no change in poi and its not bedded

 

[glbreil]

It is an amazing barrel that shoots the same clean or fouled. I have never personally seen one.

Gary

 

[Ro_Bird]

I suppose it all depends on what you are use this rifle for. For me I would consider this to be unacceptable as a tactical rifle. For a hunting rig or maybe even a match gun this might be something you can work around but in short this is a less than ideal.

 

[mrbungle]

i am having the same problem i think with a savage FCLP-K factory barreled action. i was doing ladder test for loads and as the weapon warmed up it seemed the POI rose then stablized. i am seriously thinking of having a new barrel but on.

i am going to re do the test to see if it was the loads or the barrel.

 

[loudandproud]

None.

It is an amazing barrel that shoots the same clean or fouled. I have never personally seen one.

Gary

The topic isnt about clean to fouled POI shift, it is about fouled cold barrel to fouled hot barrel POI shift.

I shot yesterday and noticed the issue again while shooting longer distances.

Shot 100 rounds over an hour or so... gun didnt stabilize until about 10 shots in.

I might bed the action and install a new shilen on it and see if the results change.

 

[usmc02xx]

If I have a shift its so minimal that im calling it my error. ive had rifles before that i thought did it, but then i realized it was all/mostly me. Im running an AO built 6.5cm in a AICS. Stiller tac 30 action and Rock Creek Barrel. Like others, i see a clean to dirty shift of about .5 inch. After 5 rounds it stays stable until about 600-700 rounds then time to clean.

 

[Darkside-Six]

I see a very small shift in POI between my cold bore and my second shot, then they all stay together. When people say their POI "walks up" after a few shots that to me usually means they are chambering a round into a hot barrel and then not firing it for a matter of time which could "Cook" the bullet so to say and effect muzzle velocity.

 

[tylerw02]

The Bartlein on my old Stiller had no POI shift. The Bartlein on my AI has no shift. No cold to warm, warm to hot. The only shift I get is when I have my suppressor off and screw it back on, it shoots low and right about .1-.2 mRad.

 

[Ro_Bird]

What ammo are you shooting? Or are you hand loading? As some others have pointed out your rounds could be "cooking" in the chamber. Probably not likely but might be something to look at, most powders these days are farly temp stable but I've seen some pretty crazy shit with .50 cal ammo over the years.

Honestly its probably just a shit barrel.

 

[HodgdonExtreme]

I had a "premium", custom, fluted (by the bbl maker), button-rifled barrel that would stack 3 shots on top of each other from a cold bore, and then begin to walk up and to the left. Slowly at first and then more if you continued shooting. By the time you had fired a 10 round (somewhat rapid) string, you'd be ~.5mil left and ~.5mil high. It would stop climbing about there, but grouped like a shotgun. Let it cool down for a good while and it would stack the first couple shots again...but start climbing.

That barrel is no longer with us.

ETA: In the barrels defense, it was a pretty light contour - light palma. I'm sure the fluting didn't help any, either.

 

[M40_A1]

When people say their POI "walks up" after a few shots that to me usually means they are chambering a round into a hot barrel and then not firing it for a matter of time which could "Cook" the bullet so to say and effect muzzle velocity.

^^^^^^This^^^^^^

Also, 30 seconds between rounds will allow the barrel to get quite warm. 1 - 2 minutes would be better, and get the shot off before it can warm up in the chamber.

 

[EXTREMEPREJUDICE]

I've never been able to attribute a change in POI relative to a change in barrel/bore temperature. I definitely know that there is a change in POI due to me, the shooter "warming up," per se especially during longer shooting sessions as the attention wanes. As always.........................YMMV.

 

[timelinex]

Graham is right. There could be a small shift in the first shot after cleaning. And there could be a small shift in a cold barrel in general (although most that are in the know, attribute it to cold shooter rather than the barrel)

However from there on in, there should be no more shifting. The only time would be with hunting rifles that have a very light profile, but this is not the case for you.

Honestly speaking it can be the shooter. Try shooting a different rifle for a couple minutes before shooting this one.. See what happens then. I use to have a problem of floating zero, where the zero would change from group to group, but found it was a parallax and form issue, not rifle issue.

With a heavy barrel, you should have no problem shooting many consecutive shots with no walking. Although, make sure not to chamber the round until you are ready to shoot, because you can in fact "cook" the round.

My savage fcpk shoots into the same ragged hole from the very first cold bore shot to shot number 20+

 

[RobertB]

My Kreigers have no shift. CCB is off though.

My bartliens have none anywhere..

Got 2 more that will be screwed on before much longer. I bet they will be the same.

 

[Pester]

How long can it sit in the chamber before reaching a temp that it impacts poi given the OP's rifle?

^^^^^^This^^^^^^

Also, 30 seconds between rounds will allow the barrel to get quite warm. 1 - 2 minutes would be better, and get the shot off before it can warm up in the chamber.

 

[mk74]

I have FLCP-K also and I do notice a shift from clean. Its a new rifle and I'm still discovering its behaviors but from what I read and watch on youtube (rex reviews) its normal.

how often you clean your barrel?

Rex actually touched on this subject. He and some other guys calls it "copper equilibrium". he actually recommend not cleaning at all your bore for about several hundred firings "clean as necessary" unless it gets really dirty.

I'm curious about what other guys here have for their cleaning regime

 

[tylerw02]

Cold to Warm Barrel POI shift... what is considered normal/acceptable.

I clean mine when accuracy starts to degrade. My latest barrel I cleaned the first time after about 250, I'm at over 800 now without cleaning again. I went to confirm my zero yesterday on 1/2" black dots. I shot five rounds that were one hole and then the sixth round turned it into an infinity symbol (sideways 8), all well under 1/2 MOA, which has been what the barrel has been shooting for the last 800+ rounds. Don't buy into the mantra of cleaning your barrel all the time. It'll tell you what it needs if you listen.


Sent from my iPhone using Tapatalk

 

[M40_A1]

How long can it sit in the chamber before reaching a temp that it impacts poi given the OP's rifle?

That's like a trick question. There's no way to answer that. The effects of sitting for five seconds may be real, but virtually unmeasurable. All powders have burn characteristics that change with temperature, some more than others, so that is a factor as well. Then there is the difference in chamber temperature versus ambient, and rates of heat convection, thicknesses of brass, space between the brass and chamber walls, etc.

So, suffice it to say the shorter the time, the less it will make a noticeable effect, and the longer between shots, the better. Many 1000k yard competitors will eject a round if they were unable to get the shot off in about 10-15 seconds, because those chambers get pretty warm and the POI will rise enough to push the bullet out of the X or 10 ring otherwise.

I found my rifle holds groups well when fouled, but don't want to chance carbon absorbing and retaining moisture, so I clean the carbon out with patches of CLP, no brush, leaving the gilding metal in the bore. Shoots just as well, and I don't have to worry about cumulative pitting. If in a dry environment and/or shooting often, then I just run a couple dry patches down the bore at the end of the day and call it good.

 

[loudandproud]

I only clean the powder out once every 300-500 rounds or so. Just Hoppes 9 and a wet patches until it comes out clean.

I only de-copper if the accuracy goes south (700-1000 rounds).

 

[M40_A1]

I only clean the powder out once every 300-500 rounds or so. Just Hoppes 9 and a wet patches until it comes out clean.

I was using No.9 before i switched to the CLP. I found the No.9 was removing more copper than i wanted removed, even with a one minute soak time per patch.

One other thing that should be done periodically is to get at the caked carbon in the throat. That carbon creates more drag and more heat, which in turn is what "shoots out" the throat. In fact, it may be more the reason for groups opening up than copper fouling. I use a patch with JB and run it in and out of the throat about half a dozen times, then a couple more passed further down the bore, then on out and done. I do this every several hundred rounds. I doubt it is removing all the carbon, but it must at least be removing some and smoothing the rest enough to bring the groups back down to size.