Actual barrel movement

R

Roy Allain

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I've been reading the "barrel vibration" thread in the gunsmith forum and one thing I didn't see and which I am interested in is "how much does a rifle barrel move during firing"? Actual up/down or side to side.

How much material should be removed from a stock to eliminate any impact effect of the stock on the barrel?

Roy
 
The other factor that increases the needed stock to barrel clearance is stock flex, and how far out on the forend that your rest the rifle on whatever support you are using. I the past. I have used the then commonly available reference of the thickness of a match book cover on the sides, where it shows, and 2-3 times that where it does not show. Obviously this is not a precise reference, it was easy to relate to and not everyone had a set of calipers handy. The only place where I have generous clearance actually showing is under the barrel at the forend tip. These are for game and Varmint rifles. For competition rifles or those where additional cooling is desirable just make sure that the gap is small enough that small animals do not have room to nest.
 
Test it.

Put the rifle together, point it at the sky and slap the forend against the barrel...... use your palm and slap it hard. Harder for heavy rifles. I'm currently playing with a heavy gun that REQUIRES an eighth inch plus of clearance using a Manners T5a stock that's been reinforced by Manners using "90% carbon fiber" process AND with two lengths of 5/16 allthread inletted thru the entire forearm with tensioning nuts out front. I had to tension the nuts up until the stock creaked and bed the chamber section of the barrel to get it to stop hitting. This is with the entire action bedded end to end. Most of the time I just leave a HUGE gap but in this case it was worth the time (aesthetically) to bed the entire barrel channel for the look as well as clearance.


How did I know it was hitting upon firing you ask??

Carbon paper.

Stick something in the gap like carbon paper ir inletting black/blue when you fire it.

I can't imagine anything less than 1/16" clear as working.... the old "slide a dollar bill" thing is a complete waste of time. Aint NO rifle stock combination gonna' isolate using the thickness of a dollar bill. Or even 5 dollar bills.... :)


opinionsby






al
 
Exactly what I have done

How did I know it was hitting upon firing you ask??

Carbon paper.

Yep the carbon paper trick works a treat.

In actual fact a barrel vibrates in a sine wave manner that spirals up the barrel as the bullet progresses along its length. The amplititude of the sine wave varies with the weight of the barrel, calibre/cartridge, and actually changes its frequency as the projectile reaches the muzzle. A bit like a steel guitar changes its note as the metal block is moved along the strings. So it pays to check with the carbon paper at various points along the barrel channel.
Andy.
 
alinwa said:
the old "slide a dollar bill" thing is a complete waste of time. Aint NO rifle stock combination gonna' isolate using the thickness of a dollar bill. Or even 5 dollar bills.... :)
Click to expand...

I agree the thickness of a dollar bill or even 5 is not enough , however if you cannot even get the dollar bill in you know for sure it needs more clearance .

Dick
 
Thanks for the good info.

But let me give a bit more info to the op.

This is a 28" SS Krieger barrel. 6.5x47 Lapua chamber. 1.25" at chamber & .900 at the muzzle. It is a Rem 700 with the HS stock. Currently just a hair less than 1/16" gap. The rifle weighs 15.25 lbs. Will be shooting either F-class 600 yds. and also/maybe 1000. It shoots in the 1's and 2's, but not consistently. I think its the clearance.

I was just curious as to how much barrel movement I could expect. I will install a new stock and the barrel channel will be hogged out to at least 1/4".
 
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