THE 408 CHEYTAC (PUSHING THE ENVELOPE)
Its not often in life you get a road to
In 1998 the latest issue of Tactical Shooter from the USA dropped through my door and I settled down for a good read, I turned to page 73 And instantly my shooting life changed, there it was in front of me the future of extreme distance shooting.
From that moment on the plan to build the definitive extreme long distance rifle based on that 408 Cheytac cartridge was never far from my thoughts, this is part two of a series of articles on the 338 RPA Rangemaster rifle and its rebuild into a 408 cal Ultra long range rifle.
The article in T.S. was based on the concept, design and construction of a new cartridge and rifle named the 408 Cheytec. The problem which was to be solved by Dr John D Taylor and William Wordman, was to create a completely new sniper weapons system including its ancillary equipment, to take Law enforcement and military specialist snipers into the next generation of battlefield situations.
PRESENT DAY OFFERINGS
An examination of present day military cartridges shows us that the 7.62 Nato, holding 56g of water is the standard bench mark for sniper weapons systems, using heavier long range bullets is affective up to 1000yards+. And is at this extreme range still a capable anti personal round, there is plenty of antidotal evidence to back this up.
The 338 Lap Mag was developed in 1982 and holds 114g of water and is considerably larger than the 7.62 with the heavier end bullets coming in at 300g there is a obviously bigger kick and blast signature, but it runs out of steam around 1500 yards and is limited in its choice of ammunition, and is only of use on soft skinned targets at its extreme edge of its range, which given its size over the 7.62 doesnt show a great ballistic advantage.
The 50 BMG which holds 300g of water was designed in 1918 as a light anti tank round but advances in tank armament soon made it obsolete for this task, throughout time it has been picked up in various special ops situations for extreme range and or its kinetic hitting power. It was famously used by Gy St Carlos Hathcock in Vietnam in conjunction with an Unertl X8 scope in a long range anti personal role, although the 50 comes with various bullet configurations including armour piercing, explosive and match, and will go out around 2500 yards it is an overkill round in its anti personal role, and its true arourmer defeating capabilities fade beyond 600yds, and the guise of a mobile rifle sniper weapon system in a turn bolt set up its not a pleasant thing to shoot due to its recoil, and of course it does give of a very large signature on firing.
It is worth noting at this point that the present darling of 1000yd match shooters 6.5x284 has a comparable recoil to the 7.62 and has a flatter shooting trajectory than the 30, 338 and 50cal and is easily portable coming in at roughly the same size and weight as a 308 rifle, various special ops units around the world have not been slow to see the advantages of this chambering.
THE NEXT GENERATION
So we can see that there is defiantly a niche hear for a new kid on the block. The 408 round was initially conceived to fill the gap between 338 and 50cal i.e. improving on the 338 balisticly and being equal to the 50 in its range and hard hitting capabilities. Cheytac Associates has a motto Technology Over Tradition and it was this use of cutting edge technology that is at the heart of this system, a completely new case was designed based on a 505Gibbs and a new 408 caliber bullet was created. The bullet is a solid copper/nickel CNC turned projectile manufactured by Lost River Ballistics Technologies with a BC of .945, LRB design there bullets around a Patented Balanced flight principle which displays some amazing characteristics.
Balanced flight means that when the bullet goes through the transonic stage they still fly true to there original trajectory unlike a standard round that once it goes transonic tends to become unstable and deviate from its supersonic flight path. The 419gr bullet fired at 3000 pfs is still supersonic at 2,300 to 2,500 yds depending on weather conditions and at 2500 yards only uses 102MOA with a flight time of 4.37 seconds, whilst the 50 using a 750g Amax match bullet at 2500 yards uses 130MOA and arrives at 4.87 seconds.
Cheytac have a second 305gr bullet called the BDR (Battlefield Domination Round) for shorter ranges which can be sent out at 3500pfs and if zeroed at 100yd has a maximum ordinate of 48 inches!! at 1000yd. This is to save the operator making multipull scope adjustments in a rapidly changing battlefield situation, just zero at 500yd and your away, with a flight time of 1 second to 1000yd this has already proved a very useful combat tool.
Another useful military byproduct of this copper/nickel bullet was although it was not designed as an AP round it displays better armour defeating properties than 50 M8 AP at 650 yds,
Cheytac have done extensive testing using a Dopplar radar system at the US Yuma proving grounds to back up all this data, In short these bullets are faster, flatter and handle the wind better than any other product, ultimately this round beats 50 cal in just about every field and has less recoil and a smaller firing signature and hence is much kinder to shoot.
The proof of this pudding is that during testing and proving this rifle and bullet combination a USMC sniper team using there standard M200 Intervention Cheytac rifle, set a three shot record of 16-5/8 inch at a mind blowing distance of 2,231yards of a bipod in a prone position, thats less than 0.5 moa at about 1 ½ miles!!
So how can all this R+D be of use to us, well the brass is of high quality with no belt and extra strengthening on the web, and the bullets have a superb BC and being a solid (as apposed to a lead core) can be pushed hard without fear of deforming or flying apart when launched. As with most cases some redesigning can improve case capacity and efficiency so if we blow out the side wall and increase the shoulder angle (improving) this gives us some extra room to experiment with different powder loads.
For our Match version of this rifle the barrel must be of heavy profile from 1 ¾ to 1 ¼ at the crown with a OAL of 34inch (this one is carbon wrapped) to reduce its weight down a little to 8lbs. The action, chassis and stock is as mentioned in my previous article is the RPA 338 Rangemaster, why RPA.. well there are lots of custom actions mainly from the U.S. that you could use for a project like this but why bother when the UK produces a proven world class product that is second to none and is on your doorstep and readily available, the bolt and action has a finish of Blanitnite-C which is both a dry lube and a hardwearing finish, this unit has a very short lock time and this gold trigger is weight and length of pull adjustable is a true delight to use.
I mentioned out the outset my intensions to use the 338 for my project and Mike Cherry MD of RPA relived the ejection port to take the larger 408 case and made an extra bolt to handle the larger bolt face. Next I took the original 408 reamer dimensions and increased the shoulder angle and with a little help from Pacific Tool we soon had the chamber and die reamers for the renamed 408 Hunter, The die blanks were from Troy Newlon whose stock in trade is supplying blanks from custom wildcatters, once all the bits and pieces are assembled you need someone who knows what there doing to put it all together, this is no job for an enthusiastic amateur so in stepped Pete Walker of Walker Custom Rifles, Pete has been building a growing reputation for turning out high class precision rifles for some years now in fact hes just moved to bigger premises to keep up with the demand for his talents.
And after a weekend of hard graft (on petes part) the job was done, at the same time Pete made a muzzle break which is designed and based on the dead Air principle that air rifle shooter use, this has an inverted cone inside the break so that the bullets nose enters the cone as the rear bearing surface exits the crown this helps stops gas getting in front of the bullet inside the break, forcing the bullet to shoot through its own gas which could disturb the bullet flight.
As with any wildcat there is an amount of fireforming to get your brass blown out to the new chamber size. The water capacity of the standard 408 case is 158g which equates 125g of Reloader 25 and that in turn will give you approximately 3000 fps, the improved version comes in at 164g of H20 and will take 130g of Reloader 25 and should allow me to moly the rounds and keep them at same velocity of 3000 fps.
OTHER NECESSARY EXTRAS
The finished gun weighs in at 18.5lbs, a fair part of which (6.5 lbs) is in the US Optics SN9 ASEARTS (Advanced State of the Art Extreme Range Telescopic Sight) 10x42x80 scope, I met Dr John Williams Snr, president of US optics at the Shot Show in Vegas 2003 and after many long discussions I decided to choose this scope because of its superb clarity and because of its elevation adjustment of up to 300 MOA (no sense in making a long range rifle and running out of scope adjustment) the more observant will notice that the windage and elevation adjustment is external this leaves all of the tube 30mm to lenses and light transmission which after all is its job. Because of its 80mm objective lens it sits somewhat higher than normal so I fitted a H.O.E. Snipers Cheekpiece to raise the eyeline back up to the correct position and make shooting it more comfortable. All US Optics scopes are made in the
Because of the rifle is slightly top heavy scope wise, I constructed a spigot in the front of the forpiece of the stock and adapted a Sako TRG bipod to fit it, this has the affect of lowering the centre of gravity to near the barrel bore axis and widening the footprint making the whole thing a lot more stable, I really like this bipod a lot of thought has gone into its design and construction, with the spigot attachment it can be fitted in seconds and the legs can fold forwards or backwards.
Finally in the interests of Health and Safety and the hearing / sanity of my fellow shooters I had a sound moderator made this one is by Reflex (supplied by Jackson Rifles) it is a shortened 50 cal version made to take the 408 bullet, this is a great piece of kit and it reduces noise and recoil down considerably.
As I mentioned in my previous article I intend to start a 1 Mile Club soon for anyone who fancies dabbling in the extreme end of things so if youve got something that will get that far and you want to have a go at testing yourself and your kit, and hopefully setting some UK records, drop me an email and I will add you to the mailing list to keep you informed of dates and venues. Finally ide like to say thanks to all the people that have helped in this project including, Mike Cherry RPA, Anthony Taylor and the staff- Cheytac, Pete Walker and A J Hunter.
Walker Custom rifles 01422 248241
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