Correct Setup of coaxial rest

[willow]

Hi Folks,

I have been having some issues of late(no, not the medical kind), and I'm hoping for some advice/words of wisdom from some of the more experienced shooters on here. So the story goes...

About a month ago I started using a Dolphin Company coaxial front rest. It most closely resembles a Farley rest, except the centre post swivels, allowing you to line up the target without having to move the entire rest. Straight away I had issues with the rifle not tracking properly (284 Win), with the front end of the rifle twisting and jumping out of the front rest. Matt Paroz immediately noticed that I did not have enough sand in my front and rear bag. I don't like to badger Matt at the range as his schedule is busy enough without being troubled on a Saturday afternoon but credit to Matt and sure enough, I managed to pack another half kilo into the rear bag and a bit more in the front bag.

I recently went out to St Marys indoor range to sight in a new scope and establish a wind zero. No issues with the sighting in and tracking of the rifle, it didn't jump out of the bag and just moved rearwards, nice and smooth. I had no trouble putting 5 rounds inside a 5 cent piece. However last weekend at Hornsby the rifle went back to its old ways, jumping and twisting out of the front rest. Suffice to say this was frustrating, but I'm sure it's my stuff up, which I'd like to try and confirm...

Now in the setup of the rest, I made sure to level the rest on a left/right basis so the rifle wasn't canted, but from memory I am pretty sure the rest was also leaning forwards towards the target and was not horizontally level in this aspect. At the time I didn't give it a second thought. I had the side tension on the front bag as tight as it would go but the rifle still persisted in jumping and twisting. I think I ended up shooting my worst ever score. Could the forward cant of the rest have resulted in the rifle jumping not tracking properly? I'm sure it's something simple as there were no such issues at the indoor range when shooting off a flat bench, but I suspect with the angle at the 300 metre mound at Hornsby and the forward cant of the front rest, this may have proved my undoing.

Sorry if this sounds like I'm rambling but I'm new to using a coaxial rest and would like to sound out some of the experts on here and sort out the tracking issues before I start praying to be struck by lightning, or some other divine intervention. I know the rifle is very capable, provided it tracks properly. I'm sure the main problem lies with me in my setup of the rest. Just hoping someone with more knowledge and experience than myself can offer some words of advice (or a kick in the arse if you happen to shoot at Hornsby).

[Tim N]

Might be worth backing off the tension on your front bag as the rifle should be able to move freely under recoil.
I used to shoot a 284 which was around 8kg and it would jump around but when I increased the weight it behaved much better.

[Send-it]

i've been through an almost identical issue over the last few months, with my caldwell coaxial rest, and have only just now got back to doing good shoots.
My rifle was also canting a fair bit upon firing and recoil.
i experimented with sand amounts in the front and rear bags, and have now found my rifle likes the following combination.
a) very tightly packed front bag,....including the bits on the sides.
b) less sand in the lower portion of my rear bag, but more sand in the ears of the rear bag.
c) less shoulder input into the but plate of the rifle
d) a 'small' amount of cant, (to the left) upon the rifle fitting into the front rest (adjust front rest front feet on the ground etc)

this works well for me now, with no canting (or recoiling) off to the sides between shots.
my score a few days ago was 119.13 so i was happy with its consistency, which helped me concentrate on shooting, rather than watch the shots bounce out to the sides due to lateral movement.
i think the biggest 'single' improvement though was the extra sand in the front rest, both lower bit and the sides, with the sides tension'd up enough to minimize all movement, yet it could still slide back smoothly under recoil.

[willow]

Might be worth backing off the tension on your front bag as the rifle should be able to move freely under recoil.
I used to shoot a 284 which was around 8kg and it would jump around but when I increased the weight it behaved much better.

What did you do to increase weight? How did it affect the balance of the rifle?

[plumbs7]

Hi Folks,

I have been having some issues of late(no, not the medical kind), and I'm hoping for some advice/words of wisdom from some of the more experienced shooters on here. So the story goes...

About a month ago I started using a Dolphin Company coaxial front rest. It most closely resembles a Farley rest, except the centre post swivels, allowing you to line up the target without having to move the entire rest. Straight away I had issues with the rifle not tracking properly (284 Win), with the front end of the rifle twisting and jumping out of the front rest. Matt Paroz immediately noticed that I did not have enough sand in my front and rear bag. I don't like to badger Matt at the range as his schedule is busy enough without being troubled on a Saturday afternoon but credit to Matt and sure enough, I managed to pack another half kilo into the rear bag and a bit more in the front bag.

I recently went out to St Marys indoor range to sight in a new scope and establish a wind zero. No issues with the sighting in and tracking of the rifle, it didn't jump out of the bag and just moved rearwards, nice and smooth. I had no trouble putting 5 rounds inside a 5 cent piece. However last weekend at Hornsby the rifle went back to its old ways, jumping and twisting out of the front rest. Suffice to say this was frustrating, but I'm sure it's my stuff up, which I'd like to try and confirm...

Now in the setup of the rest, I made sure to level the rest on a left/right basis so the rifle wasn't canted, but from memory I am pretty sure the rest was also leaning forwards towards the target and was not horizontally level in this aspect. At the time I didn't give it a second thought. I had the side tension on the front bag as tight as it would go but the rifle still persisted in jumping and twisting. I think I ended up shooting my worst ever score. Could the forward cant of the rest have resulted in the rifle jumping not tracking properly? I'm sure it's something simple as there were no such issues at the indoor range when shooting off a flat bench, but I suspect with the angle at the 300 metre mound at Hornsby and the forward cant of the front rest, this may have proved my undoing.

Sorry if this sounds like I'm rambling but I'm new to using a coaxial rest and would like to sound out some of the experts on here and sort out the tracking issues before I start praying to be struck by lightning, or some other divine intervention. I know the rifle is very capable, provided it tracks properly. I'm sure the main problem lies with me in my setup of the rest. Just hoping someone with more knowledge and experience than myself can offer some words of advice (or a kick in the arse if you happen to shoot at Hornsby).

Hi Willow , I'll share some of my experiences for what they are worth!

Yes having your pedistal rest out of plumb can cause vertical! So a plumb rest is quite important!

I remember watching the late Cam Mac and watching his rifle buck like a mule with rifle torque at various Opm's , but he must have done it exactly the same every time . As he was part of the 2013 fowc Raton team. There is a vid of it somewhere if somebody is kind enough to post as it was very interesting!

Something that seems to control rifle talk is a low c of g . That is the barrel as close to the front rest as possible. Another thing is adding ski rails to the sides of ur for end . Creating a space or slight air gap , so ur fore end doesn't sessaw at the middle of the fore end and front sand bag.
There is so much that can cause vertical one could Wright a book on it ( maybe somebody should !)

Rear bag stability is a huge factor that we did prove at a 1000 yds with a known tuned rifle and just Changing the resr plate !
Shoulder pressure is another , some free recoil like Cam did ( it tagged his collar bone a few time and cut him). Others preload and myself does in between .
Every stock recoils different . For instance my manners thumb hole stock , I'll be more in line with the rifle . My Mac F class stock I'll be in a different position again.
A little of topic , but this I believe maybe a good argument to shoot just one Rilfe / stock combo.

Getting back to ski rails , I was trying to find what I could put on my Mac stock to stop the rifle torque . I was fitting off a new house when I saw a Raven door weather strip and bingo that was what I was looking for . It's extruded aluminium so it's light . Had double sided tape on one side , so no glue to devalue my rifle. And it was only $13 at the local hardware store.i just pulled the black fury stuff out , cut to length and done deal. Made a large improvement in tracking.
Talc powder can also help too!

Also found just how I positioned my thumb and elbow made huge difference in vertical and in velocity.
Preloading seems to net the most velocity as majority of the energy is spent propelling the pill forward and not the rifle backwards.

I now position my sand bag so my elebow , thumb and shooting hand is hopefully in the same spot every time !

You may just have to have a 100 rounds a video camera and try a heap of different positions and watch back on video!
I did this just recently to fix my vertical problems and it was very scary! As you could clearly see I am going bald !! but seriously I picked a few things and on the most part , my rifle tracked satisfactorily !
Maybe just rat a tat tat on With 24 rounds isn't achieving very much on a Saturday club match. Maybe more detailed research and developement is needed to find the fault ( faults ) .
Hope this helps . Regards Graham.

Ps ! Also watch ur coaxial hand isn't bouncing around under recoil causing ur vertical too!
Sorry , I keep thinking of other things . A square edged fore end is a must . A anti torque plate maybe needed . Something like what Sinclair intl offers. For my manners stock a good mate machined one up for me .

[willow]

Thanks very much for replies guys. Some informative comments which has given me a few things to think about and try out. I'm sure I'll get this thing tracking smoothly soon.

[Tim N]

What did you do to increase weight? How did it affect the balance of the rifle?[/quote]

I needed to add around 2kg so I made a plate the same shape as my recoil pad (6mm) and welded 2x pieces of 24mm roundbar approx 300 long, removed the filler foam from the stock(a McMillan MBR) and bolted it between the recoil pad and stock, the difference was very noticeable.
This made the balance point near the front of the action and recoil was reduced