Gunsmithing strange vibration when firing my .308

[maccrazy2]

Hello all. I was at the range yesterday and I took a .308 savage action rifle I pieced together a while ago. I just had it out about 2 weeks ago and shooting the same ammo it seemed normal. Yesterday from the first shot I got a vibration like a tuning fork for what I would estimate at 1/2 second long after firing. It was very noticible and unusual for this rifle. After feeling this I immediately unloaded and looked for something loose, barrel, stock screws, scope&base all were tight. This stock is not bedded,it is the oem stock for the action. I have aprox 300 rounds thru this setup and have not felt this before yesterday.
After determining there was no loose barrel I fired 19 more rounds and felt the vibration every shot. Accuracy loosened up a little bit. but, I was concentrating more on the feel than the shot placement so that may have been due to me. One other thing, I used 10 rounds from the same box I was using on the last outing so there was no change there. So any ideas are appreciated. I am not sure what to do at this point other than to tear it down and see what I can see. Chris.

 

[kombar]

Re: strange vibration when fireing my .308

Sure it's not your hearing protection contacting the stock?

Are you feeling the vibration or just hearing it?

 

[Phylodog]

Re: strange vibration when fireing my .308

Heard of barrel harmonics?

 

[1SMALLJOHNSON]

Re: strange vibration when fireing my .308

Run a dollar bill between the stock and barrel. Determine if there's any contact. Pull the action from the stock. See any wear marks? Smoke the action/barrel with a burning styrofoam cup. Insert back in stock and torque. Remove carefully. See any weird marks? Check barrel torque.

 

[300sniper]

Re: strange vibration when fireing my .308

is it your bipod springs? i hear them when shooting my 300wm off of concrete or a hard bench.

 

[Kells81]

Re: strange vibration when fireing my .308

got a vortex on this rifle?

 

[Greg Langelius *]

Re: strange vibration when fireing my .308

I traced a similar sound down to my bipod springs.

Try taping them tight against the legs and do it again. If it's not there anymore, you've identified your 'kabong'.

Greg

 

[NOMISS]

Re: strange vibration when fireing my .308

I had a Remington 700 VLS .308 that had a similar problem, i found that the recoil lug recess in the stock was wider than the recoil lug on the action, and that on firing - the action was "jumping" about in the recess causing the groups to open and the energy from the discharge to re-verberate down the barrel causing that annoying vibration, this kind of thing just happens quite a lot, so dont worry too much!
Solution - bed the recoil lug, or better yet pillar bed the reciever, be carefull not to gorilla the action screws tight afterwards, but either way that vibration will be gone.

 

[ChadTRG42]

Re: strange vibration when fireing my .308

Is there any adjustable cheek pieces on the rifle? I've had screws come loose before inside the adj cheek. Check bipod, and anything that might have fallen into the bottom of the stock.

 

[NOMISS]

Re: strange vibration when fireing my .308

+1 what ChadTRG42 has said too.

 

[padronanniversary]

Re: strange vibration when fireing my .308

ChardTRG hit it right on the nose. I had the same exact issue with mine as well, it took me about 20 rnds to isolate it. I had duct tape all over my stick and scope trying to figure out what it was.

 

[FNuser]

Re: strange vibration when fireing my .308

This happened about 20 years ago to me I was shooting an old scope that was too long for the distance between mounts, It was a Redfield 3200 and the scope was "twanging" everytime I pulled the trigger it was a 6-284 so there wasn't alot of recoil but the amount of scope hanging off the front had to settle down before I could put another one downrange other then that every thing was fine. I've noticed that alot of the Burris scopes seem long also can you list some more specifics about your rifle?

 

[maccrazy2]

Re: strange vibration when fireing my .308

Wow thanks for all the replys. I suspect it is somthing to do with the action vibrating in the stock. The harmonic type vibration that I was feeling I have not felt any of the previous trips to the range. It definately does not feel normal.
to list the specifics on the gun.
action is a savage LA (originally a .270cal rifle)
tubb .250 recoil lug
adams&bennet stainless fluted bull barrel in .308 caliber 24in long
rifle basix trigger
burris rings
tasco world class plus 8-32by50 scope (no laughing, I had it laying around)
the stock is the original and does not have a bipod or sling swivels.
I was resting the stock on a stuffed rifle rest bag, the barrel was not touching it.
I also checked today and there is nothing inbetween the stock and the barrel. I will tear it down this week and try to locate the cause. I have a boyds stock to put on it but I want to make sure there are no other issues before I start messing with that.
Thanks again for all the suggestions.