Target Sports

TACTICAL UPGRADE: TAKING STOCK

Created on 14th May 2009

ROB HUNTER thinks he can improve the AICS stock - and here he sets out how to do it

Accuracy International rifles were originally designed by the late Malcolm Cooper and have been around since 1978. In 1989 the ACIS stock kit was launched for Remington 700 rifles as an aftermarket stock option that also gave increased magazine capacity. I have personally never been a big fan of the AI stock. Some like how it looks, others not but, when it comes to stocks, I'm not much concerned with what they look like. I just don't find the ACIS particularly comfortable to use and have difficulty in obtaining a good fit with them. I have a pet theory that although Malcolm Cooper spent considerable time and effort in designing the AI rifle, rather less time went into perfecting the fit of the AI stock.

Readers may ask: "ok, if this stock is on one of the world's most popular military sniper rifles, what problems do you have with it?" My initial gripe is that it's hollow: it has a metal internal frame and an external shell or skin. This is a combination that can make a stock give off a distinctive noise or ‘ring' on firing and be audible to the shooter. This is because the metal-to-metal mating transmits a harmonic tone and the plastic shell acts like a guitar sound-board (the old Blaser 93 Tactical suffered a similar problem).

Secondly, the whole stock is very square in its section at the grip, forward grip area and the cheekpiece, which to my mind is not very user-friendly to the hand or the cheek. Thirdly, I feel the grip positions the hand poorly in relation to the trigger, placing the trigger finger on the trigger blade almost on the second finger joint for many shooters: this gives poor trigger control and release. Finally, the bolt has a long rearward stroke on the AI action and to accommodate this, the cheek rest is a long way back. In consequence the tapered front of the cheekpiece has the shooter's head falling off the front of it rather than being supported by it. This can be overcome by increasing the length of pull (LOP) by adding butt spacers, but this then means the scope must be moved back too.

The normal prone shooting positions means that human contact is made with the rifle at three points: the shoulder, the cheek, and the grip/trigger finger, and these are the points where the shooter can impart movement to the rifle via heart beats, breathing, flinching or just a bad or uncomfortable shooting position. This last one can be brought on by a badly-designed or poorly fitting stock. One of the biggest things that we at Hunters Of England are involved with is trying to assist in the fit of the rifle to the shooter via our sniper cheekpiece. This is an anatomically contoured neoprene lace-on pad which provides a comb raiser and improved cheek-weld for the shooter, in a prone position. Our back bag makes a rock-solid support for the heel of the rifle, which only leaves the grip. The grip is arguably the most important of the three as it involves the trigger finger; this is a very tricky area if the fit is not perfect as there are no aftermarket accessories to aid the fit between man and machine.

The success of my 6.5x47 rifle in last year's tactical competitions has spawned a lot of similar looking rifles, which is very flattering, so I wasn't surprised when a friend asked me to build him a similar rifle, but his choice was the AI ASICS stock. As the customer is always right I rang up Graeme Clark of Sporting Supplies (Accuracy International distributor) to place the order, which landed on my doorstep two days later. I also need a stock for a new project .260 Imp competition rifle for next year so I took the opportunity to have a close look at what I could do to improve and customise the fit to suit me.

The external parts or ‘skins' of the stock are moulded polypropylene and can be easily removed via six bolts. The internal framework of the stock is a very well-designed piece of engineering with an internal aluminium framework running the full length of the stock, which also incorporates a magazine well, sling attachment points and in the case of this model, a very strong hinge for the folding stock.

Improvements

After much inspection and head scratching I came up with the following improvements for this stock.

The forepiece: the skins of the stock are approximately 5mm thick at the bottom underside corner of the fore-piece and can stand to have the sharper corners taken off them without compromising the strength of the fore-piece ‘skin'. This makes it more user friendly when carrying, or for ‘off hand' shooting.

The cheekpiece: the height adjustable cheekpiece on this stock does go some way to address the fit for the shooter but it's still rather square in profile and made from the same hard plastic as the rest of the stock. This being a specialist subject area for Hunters of England, I re-shaped the original cheekpiece, taking off the sharper corner then shaped some very high density foam and attached it to the cheekpiece. I then shaped the foam to compliment the angle of the jaw to cheek found on the human face. This is the ideal set up and, when positioned correctly for the individual shooter, makes for a very comfortable place to rest the face on. If done correctly it also prevents canting of the head whilst on the rifle. Finally, to stop the foam absorbing water we covered it with a fabric tape, which allows the finished job to take on the final paint job.

Length of pull: this is an area that lots of people overlook, or just take what they are given by the manufacture. DON'T! If the stock gives you the ability to adjust the LOP to fit you then you should take full advantage of it. Try this experiment: mount the gun with your eyes closed when your head is in a comfortable, natural position (i.e. not craned forward or pulled back or rocked over to the side) and open your shooting eye. If you have to alter your position in order to see through the scope then you may have a cheekpiece or LOP issue. By adding AI spacers I increased the LOP on my stock by a full 1" to make it perfect for me.

The grip: this is the trickiest area to deal with as there are two aspects to this job. The first job is to make the grip fit the hand and secondly to alter its position and profile so the trigger finger can correctly engage with the trigger blade.

As this operation required cutting into the grip I needed to internally strengthen the area, so I filled the compartments in the grip with a liquid plastic. I then made a wrist shelf to help support the hand and drilled and tapped this into the base of the grip, allowing enough of a gap to fill with more mouldable plastic. Finally, using more of the plastic, I added a palm swell, finger grips and a thumb shelf. This amounted to a complete re-work of the entire grip.

The trigger unit I had planned for this project was a Jewel, which also helps as the trigger shoe is in a more forward position than the standard AI. The aftermarket replacement trigger, supplied by Peter Jackson of Jackson Rifles, has a fully adjustable setup that would also be an excellent choice for this project.

Once everything had cured off and additions had been double-checked the stock was re-assembled to check our alterations hadn't impacted on any other areas of the rifle, and fortunately the action, magazine well, feeding and the folding stock all worked as they should. To give the finished job a uniform texture I sanded back all of the stock skins to give a ‘flat' matte appearance. Finally, all that was left was to give the job a quick coat of temporary paint while attentions turned to the barrel and action.

We haven't altered the stock's appearance by much but, by putting some work into these three areas, the fit and handling has improved 100%. I accept it's no prettier than it was but, as I said, I don't care what a stock looks like so long as it works, and this one now works. In fact it now fits me like a Saville row suit!

You can catch up on how the re-worked ACIS stock performs with my new project rifle build, a .260 Imp Tactical Rifle, in next month's magazine.

Thanks to AJH Engineering for their help with this project. For all AI products contact Graeme Clark at www.sportingservices.com.

TACTICAL UPGRADE: TAKING STOCK

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TACTICAL UPGRADE: TAKING STOCK

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