PDA

View Full Version : how to tell if you need a pressure point under barrel



acemisser
08-26-2016, 04:04 PM
At the range a guy with a varmint barrel was having trouble with accuracy
as far as getting any kind of groups..I told him maybe it needs a pressure
point..So I told him I would ask you guys about it.HOW does one know if that
might be an issue,,or point me in the right direction to find out..:confused:

BillPa
08-26-2016, 07:34 PM
Slip a few business cards between the barrel and the stock forend. It will change the POI but will give an idea if a PP is needed. Its how I initially discovered my 270-08Imp shot better with than without.
Bill

Nor Cal Mikie
08-26-2016, 11:30 PM
Bill covered it!!

RC20
08-27-2016, 12:06 AM
Sometimes it works, sometimes not. Compensating for other issues but its a lot easier sometimes to accept it works than find out what the issues are.

Still trial and error though the old Military rifles used it, probably because it was the easiest way to tone down other variables that would have taken far too much time to deal with.

For the most part free floating with pillars and or receiver bedding is better. Not easy stuff to work with.

BillPa
08-27-2016, 01:53 AM
In days gone by some would put two threaded bushings w/screws in the forend at 5 and 7 o'clock, the screws externally adjustable to increase-decrease the upward pressure on the barrel to 'tune' it. After finding the sweet spot the bushings-screws were either left in place or a pad made then the bushings-screws removed and the holes plugged.

Bill

jpx2rk
08-27-2016, 06:37 AM
Slip a few business cards between the barrel and the stock forend. It will change the POI but will give an idea if a PP is needed. Its how I initially discovered my 270-08Imp shot better with than without.
Bill

Is this a "trial & error" method where you will need to move the business cards around, or leave them at a "tight spot"? Just curious about the steps to try this method.

BillPa
08-27-2016, 08:31 AM
Is this a "trial & error"

Pretty much. Its only a rough indication if a PP may help.

Bill

yobuck
08-27-2016, 08:54 AM
As I recall some of the earlier model 70 Win had a screw under the barrel for applying pressure.

acemisser
08-27-2016, 04:24 PM
well..he tried it and the accuracy was about 100 percent better..That was at 100 yards.
But he did have to resight it and the point of inpact changed.I was totally amazed.
This was with a savage 10 in 243 cal..He is happy as a pig in ****..lol

phshrmn
08-28-2016, 07:04 PM
Would this explain why my 7-08 seems to shoot first three well but then wanders?

Sent from my STH100-1 using Tapatalk

Justin.D
08-29-2016, 04:14 AM
Would this explain why my 7-08 seems to shoot first three well but then wanders?

Sent from my STH100-1 using Tapatalk

Highly unlikely, your issue sounds like the barrel getting hot. Try shooting slow and see what happens. Pressure points on the barrel is a pretty rare "fix".

phshrmn
08-29-2016, 01:09 PM
Highly unlikely, your issue sounds like the barrel getting hot. Try shooting slow and see what happens. Pressure points on the barrel is a pretty rare "fix".
Thanks. I shoot slow and three shots tend to heat the barrel so I leave it cool a bit and shoot the next ones much slower so it is about the same temp - noticeably warm to touch, not smoking hot.

I've only taken it out twice to sight, so it can still be the shooter not shooting straight. Even in the sled, I might get jumpy or start rushing. I do better with my other rifles so wondered if there was something happening when the gun heated up and created a pressure point somewhere. Just thought this thread was interesting.

I disassembled the gun to clean it and thought I might have over torqued the bolts but checked and they're all okay. I didn't use a torque driver though.

I'll shoot some more and see if it's the guy shooting that is the problem.

Thanks again.

Sent from my STH100-1 using Tapatalk

Justin.D
08-30-2016, 10:18 PM
Thanks. I shoot slow and three shots tend to heat the barrel so I leave it cool a bit and shoot the next ones much slower so it is about the same temp - noticeably warm to touch, not smoking hot.

I've only taken it out twice to sight, so it can still be the shooter not shooting straight. Even in the sled, I might get jumpy or start rushing. I do better with my other rifles so wondered if there was something happening when the gun heated up and created a pressure point somewhere. Just thought this thread was interesting.

I disassembled the gun to clean it and thought I might have over torqued the bolts but checked and they're all okay. I didn't use a torque driver though.

I'll shoot some more and see if it's the guy shooting that is the problem.

Thanks again.

Sent from my STH100-1 using Tapatalk
Most people strive to free float the barrel because pressure points create irregularities and conditions that change based on the amount of pressure and twisting of the stock, so I would check to make sure your barrel is free floated. You could also try glass bedding the action, lowering the trigger pull to decrease the chance of you pulling it off target, torquing the action screws, etc. However if you notice its a consistent 3rd round flier my guess is its a heat issue.