Hot barrel

[VSS]

It's just a character of your particular rifle Tim. I'd be happy with it just climbing a bit.

Accepting the idiosyncrasies is all part of being a Parker-Hale owner, that much I do know!

But I do need at least one cold barrel shot to land roughly in the right place on paper before I go stalking.

Once I get out there on the deer everything will be fine. My calmness will return, and they will drop down dead.

I've just got to get over this sodding zeroing business first!

 

[VSS]

You may find once you have over done the shot string the heat will soak into the next round you chamber, it would need to be very hot for this to happen. Speeding up the powder burn rate, that then increases muzzle velocity and you will get less drop in the trajectory, giving you the rising POI.

This will then not translate into true poi change when you adjust the scope due to muzzle velocity variation in each shot fired. It will depend on how long the round is chambered for and various other factors allowing heat to soak into the case and powder.

Then when the barrel cools the poi drops back down as the muzzle velocity drops and your poi shifts back down.

I shoot all my load development and zeroing groups over a chronograph so I can gather more velocity data for better ballistic calculation accuracy and to make sure I dont stray into this exact issue.

Thank you. That's very helpful.

^ This ^ especially if your barrel Channel has a pressure point built in like some older wooden sticks do.
KB.

I removed the pressure point a long time ago, and made the barrel free-floating.

 

[enfieldspares]

But I do need at least one cold barrel shot to land roughly in the right place on paper before I go stalking.

Reminds me if this:

When my brother was "in the job" they would shoot two groups at the same time with their 'scoped rifles that they used. They would load two rounds. Fire the "cold barrel" or more correctly barrel at ambient temperature round on the left target and then fire the second round on the right target.

They would then let the barrel go fully back to the ambient temperature. And repeat. This was done to give two targets. The left of five shots and "cold barrel" aka ambient temperature and the right target the group made by that second shot. They'd then set a zero accordingly.

That may seem excessive but if you were dealing with "minute of head" at whatever distance or "minute of exposed body part through a small gap" it needed to be know where both shots would be relative to point if aim taken if two shots had to be fired in quick succession.

For what we do, stalking deer, it isn't needed.

 

[hairlesshunter]

This was 10 shots in quick succession - 6.5x55 from 20” barrel Sauer 202. I assumed it was heat but could just have easily been me…

Hi tarponhead very interesting I would have love to seen the 1st and 10th shot
Shot at a different bullseye or one ether side of the 10 group at a different bullseye
Nice shooting

 

[Trickyd66]

@VSS have you tried a A3 size target with multiple aim points, one shot at each and see where you are from that? (More than 2 shots at the same point on a paper target and I either loose concentration or if things are going well loose it trying to get the "perfect" group.)

I know it's not 270 distance, but on a 35m with 22lr if I'm shooting at a marked target I am all over the place, if I put a shot on a plain card, I can get the next four touching.

 

[VSS]

@VSS have you tried a A3 size target with multiple aim points, one shot at each and see where you are from that? (More than 2 shots at the same point on a paper target and I either loose concentration or if things are going well loose it trying to get the "perfect" group.)

That's a good suggestion, thanks!

Sounds like you experience some of the same difficulties as I do, when shooting at paper targets.

 

[Trickyd66]

That's a good suggestion, thanks!

Sounds like you experience some of the same difficulties as I do, when shooting at paper targets.

The joy of starting shooting at 10 with a webley vulcan, tin cans /12 bore cases, apples etc. As targets. Rarely a paper target. too much pressure to put all the shots in the same place on one piece of paper.

If I could have seen where the previous shots went on my DSC1 I wouldn't have passed

 

[timbrayford]

What's the general effect people see in respect of POI and grouping as barrels heat up?
My .270 appears to throw shots higher and higher as the barrel gets hotter and hotter, but I'd like to know if that matches other people's experience. Just in case I'm blaming hot barrels for some other fault.

No difference with my 270

 

[kieran222]

When zeroing in a new scope I will bore sight it as 25m, then one shot at 50m, rough adjustment if required and possibly one more at 50m and then three shot groups at 100m. After each three shot group I will walk to the target, check adjustment needed and then after adjusting try another three shot group on another clean target. I use a large piece of cardboard with multiple bulls eyes marked. Its generally only two or three groups needed.
I think that you would be best to get into a routine and build in time to let the barrel cool down. It's important that your zero is for a cold barrel as that's all you will use for stalking.

 

[VSS]

When zeroing in a new scope I will bore sight it as 25m, then one shot at 50m, rough adjustment if required and possibly one more at 50m and then three shot groups at 100m. After each three shot group I will walk to the target, check adjustment needed and then after adjusting try another three shot group on another clean target. I use a large piece of cardboard with multiple bulls eyes marked. Its generally only two or three groups needed.
I think that you would be best to get into a routine and build in time to let the barrel cool down. It's important that your zero is for a cold barrel as that's all you will use for stalking.

I did as you describe, but without the time for barrel cooling.
I hadn't expected it to be a problem, but having not fired the .270 for a while I think I got a bit overexcited

(It does make such a lovely big bang without a mod ).

 

[Smellydog]

The joy of starting shooting at 10 with a webley vulcan, tin cans /12 bore cases, apples etc. As targets. Rarely a paper target. too much pressure to put all the shots in the same place on one piece of paper.

If I could have seen where the previous shots went on my DSC1 I wouldn't have passed

I hate shooting at paper also. I'll stick a rock up first and whack it.
I also shoot at cards the size of the kill zone for which that rifle is used. Off a tripod I can generally call a bad shot out and know when one was good. As long as they are on the card in happy. I'll check zero frequently but not shoot groups unless developing a load.

 

[VSS]

I hate shooting at paper also. I'll stick a rock up first and whack it.
I also shoot at cards the size of the kill zone for which that rifle is used. Off a tripod I can generally call a bad shot out and know when one was good. As long as they are on the card in happy. I'll check zero frequently but not shoot groups unless developing a load.

Once I've got the zeroing process over and done with (which I don't enjoy), the only time I pick up my rifles is to kill things. I'm better at that than I am at zeroing.

 

[HonestJohn]

My favourite way to check zero is simply to out out an old coke can with bottom facing me. Shoot it, if it’s a hit, it’s clearly visible, do it again. If it’s a hit, the rifle will put around where it matters. Go home. I’m a victim of the paper target rabbit hole sometimes too

 

[slider]

2 X .270's here.
Browning X (featherlight fluted barrel) seems to remain true when it gets hot but I need to take my time when zeroing the Tikka T3.
All that said, the cost of copper ammo doesn't exactly encourage target sessions!!!. And I know have a digital scope on the T3 which has the one shot zero function (but still 3 or 4 for peace if mind)

 

[tarponhead]

Hi tarponhead very interesting I would have love to seen the 1st and 10th shot
Shot at a different bullseye or one ether side of the 10 group at a different bullseye
Nice shooting

Oddly it started as a 3 shot 1moa group at 100 yd POA the red square and then tightened up for the next five and I don’t know where the last two went but within the group shown. I was testing 140g factory ammo a new to me Sauer 202 that had a new barrel in 6.5x55. Typically, it like expensive Norma Tipstrike - but with that accuracy, I’m happy to spend £3 to drop a deer how and where I want to. And do I did - pinned a fallow in a slightly awkward quartering shot through a brush tunnel, at the bottom of a steep wooded bank. I squeezed the trigger with certainty on where the strike would be.

 

[gixer1]

The specific rifle and how it is bedded is going to decide which way it shifts POI, every rifle will be effected by thermal effect in some way - light sporters more so than a heavy bull barrel target rifle.

Regards,
Gixer

 

[gixer1]

This was 10 shots in quick succession - 6.5x55 from 20” barrel Sauer 202. I assumed it was heat but could just have easily been me…

Tell me you shot two eyes and a nose as well!?!