Off-Set Stocks

[TTBS28]

Hi All,
Hope you can help with an answer to what might be a basic question. I am planning to modify a timber stock for use as an F-Open rig. At present the stock torques noticeably to the right when fired. It stands quite high at the front end so the plan is to reduce it significantly in height and add just enough material to produce a low riding stock, scalloped out on the underside to assist the bag riding and extend it to the side as an off-set stock. The question is: What side do you build the extra material? My impression is to build it out on the right hand side to throw the pivot point further to the right to resist the torque BUT images that I have seen show build ups to the left. Can anybody give me the logic as to why the stock build up should be to the left?

[ecomeat]

Because your right hand twist barrel torques left first, but you don't see it coz your eyes are shut

[williada]

I was scared Tony was going to give a discourse on Newton with regard to equal and opposite forces. TTBS28 it is not worth the trouble. The torque issue is not a real problem, bag handling is. Its best to have the balance right fore and aft and probably a lower centre of gravity closer to the bore line. Because the barrel lift is more easily managed. If you want to reduce torque add weight to the rifle and use high scope mounts. I think I would rather use an offset scope and use my left eye than use an offset stock. The bullet has long gone when you feel the torque. David.

[ecomeat]

worth considering that a couple of names come to mind of top performers who do use an offset....to the Left ...stock :
Dave McNamara, Cam McEwan.......FCWC Gold medallists
Lindsay Crombie, Craig McGowan .....Brisbane RC members who were first and second respectively in the 2014 QRA LeadUp event, and have won the last three SE Qld OPMs.
Dave Macs is "home altered", with photos online in an old post about stocks . Try a forum search for "offset stock".
Craig McGowans is home made of aluminium, and every time he beats me (every time we meet) i tell him how ugly it is. Lindsay Crombie designed his own, and made it with CNC equipment at work.....and its that bloody good and that popular that they are now manufacturing them for sale against orders, for approx $1250-$1300
I hope that all four of them get rid of their offset stocks before the NRAA Queens in June

[ecomeat]

When treading on McGowans foot as he shot didnt alter his score, i just watched him shoot on Sunday (hoping to psych him out ) and his 7mm Shehane has to be the smoothest riding, lowest torque 7mm rifle that i have seen shoot. My own McMillan F Class stock with a straight 284 Win at maximum weight is very mild mannered, but Craigs "torque" is noticeably less again.
LETS BAN OFFSET STOCKS !!

[williada]

Tony, those guys could shoot a stick. Great response hmm. David.

[TTBS28]

Thanks Tony / David,

Wow !! Did the search and there's a mountain of comments on the subject. Will take me quite some time to wade through it.

David, I am a leftie so I am already using my left eye !!!

So, without going into too much theory, it is correct to build the offset to the left ?? If so, still defies my simple logic of building it to the right to increase the pivot point and therefore minimize the twist. Surely you don't build it to the left to build in a bit of weight on the left hand side ( I know, this sounds dumb but it's the only logic I can think of for building it left ).

Regards.......Jeff. Roberts.

[ecomeat]

Jeff,
Have a look at these old short videos that i did ages ago
viewtopic.php?f=5&t=5727&hilit=offset+stock
Dave Macs SAUM and Alan and Cams Shehane's show more torque, as those southern sissys are using 6mm and 6.5mm in the first two.
Tony

[AlanF]

Jeff,

Its what Tony said initially. Every so often Tony squeezes a fact in amongst all the instances of "that which is not so" . What you see is the clock-wise "bounce". The initial torque is anti-clockwise.

FWIW I tried an offset stock and abandoned it because the uneven pressure on the front bag was pushing the sand from one side to the other. I now have a stock with an ultra low profile, and plenty of weight forward, and torque is no problem.

Alan

[TTBS28]

Thanks Tony / David and Alan, Appreciate your thoughts and the videos will check out later tonight. Should have searched the subject on the forum first - can't believe how much info is out there.

Tony - Now Now !! That's enough about those 'Southern Sissy's" !!! For four years now I've been using a 6.5 x 47 and there's nothing wrong with that. Having a chamber prep'd in 280AI at the moment and this is the reason for the questions. The 6.5 is quite sedate but the 280 will need a bit more attention.

Tony / Alan - To be honest I thought Tony was just messing around with his 'eyes shut' bit. OK - If the initial movement is left then that would explain the reason for development on the left side - makes sense.

Alan - Also take on board your comments re building it LOW etc. When you mentioned balance in the rifle do you mean actual rifle balance fore and aft when held in the hand OR weight distribution over the front rest? Obviously, if you move the front rest stop forward it puts more weight on the front sand bag and vice versa.

Thanks..........Jeff.

[williada]

Sorry Jeff, I had to take a call. Alan has given good reasons with out going into the physics. My real argument is that the torque is a relative after effect in the delivery of the shot. If there is benefit to bag handling from an offset stock it only helps you to get onto the target quicker for the next shot. Alan has mentioned other ways to achieve the desired bag handling.

Actually I have considered an offset scope because by right eye is deteriorating. But my experiences with an outrigger in TR have dampened that idea. Being very interested in rifle tunes, I feel the offset has a tendency to interfere with the harmonics delivering accuracy to the bullet. I like to have the centre of gravity aligned in the vertical plane. Statistically we can all shoot well up to about 700 yards according to Alan's data, and so I would feel offset stocks would do well up to that distance, then after that scores deteriorate.

Its the long ranges where matches are won and lost. Everything has to be right for 1000 yards. The offset stocks tend to toss those angular groups making finding a tune that bit harder as Craig may have discovered. Gravity tuning seems to work better in the vertical plane at 1000 yards.

Any rifle that is out of tune usually has bad bag habits and the torque get the blame, rather than getting the balance of the gear right. Just my opinion. Cheers. David.

[pjifl]

I think there is more to be gained by experimenting with the anchoring, weight and geometry of the rear bag.

Peter Smith.

[ecomeat]

Jeff,
it it is of any value, three years ago when i got a bit serious about F Class, I was absolutely certain that MY rifle torqued right, and only right. I questioned online why these blokes (Dave Mac, Cam and others) were offsetting fancy custom stocks to the left, when my torque was clearly to the right
After subsequently watching a few rifles closely, i realised that i had to be shutting my eyes to be missing it
I think its just a normal reaction to the recoil and noise, so i 'fessed up to having been a real girl with recoil. Thats when Bruce Moulds told me online that its quite OK to "know your limits", which made me feel a lot better about myself

[ecomeat]

Tony - Now Now !! That's enough about those 'Southern Sissy's" !!! For four years now I've been using a 6.5 x 47 and there's nothing wrong with that. Having a chamber prep'd in 280AI at the moment and this is the reason for the questions. The 6.5 is quite sedate but the 280 will need a bit more attention.
.

Sounds like the SA Team Rifle calibre for the National Teams has been identified

[TTBS28]

Thanks Dave and Tony, I'm starting to get the drift here. Will get back tomorrow night with a summary of my learnings.

SA Teams - Sorry Tony, I'm not of a standard to make such an Event - too many better prepared guys around to compete against down here. Besides that - they wouldn't want an old fart like me cramping their style. AND , you'll have to wait and see what SA are developing for the Brissie Teams Event. It's all happening down here including the famous SA shirts and jackets !!!

Regards.......Jeff.