First Long Range Build Completed

longarm338

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Apr 13, 2015
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Hello everyone. I just finished up putting together my first dedicated long range build. After careful consideration, I came up with a bunch of criteria that it would have to fit in. It would have to be powerful enough to hunt with out to a minimum of 1000 yards, fit in a standard Remington 700 action, and be able to magazine feed with the latest in monolithic VLD solids seated to the lands.

With all that in mind I settled on using a short action case in a long action. That would allow for magazine feeding of soild copper VLD projectiles. What I wasn't sure of was if a short action case would have enough boiler room to launch a 250 gr projectile with sufficient velocity to expand at 1000 yards. I selected on a 338-300 WSM and Cutting Edge's 250 gr LAZER single feed projectile. Quickload showed i should be able to push them to the low 2700 fps range. It expands down to 1500 fps and with a g1 bc of .67 should expand out to over 1000 yards.

So I got down to ordering parts. I ordered a Shilen 27 inch #6 contour select match barrel with a 1-9 twist ratchet rifling and topped it off with a Lil Bastard muzzle break. For the action I chose a Stiller Precision Predator long action. For the bottom metal decided to run Wyatt's extended detachable box mag for a 300 win mag. That allows for magazine feeding with even the longest vld projectiles. For the stock I selected a Bell and Carlson's M40 Varmint Tactical Stock with an aluminum bedding block. Being this is a long range rig and will most likely be shot prone, the angled forearm allows for minute elevation adjustments simply by sliding the rifle forward or rearward on the bag. The trigger is a timney flat trigger and for optics its wearing a Vortex Viper PST 6-24x50 scope. Total package weight comes in right at about 12 lbs.

Even before I got all the parts in I ordered a set of reloading dies from Redding. Case forming is easy. Simply take 325 WSM brass and run it through the FL die and you're done. I did make one modification to the throat of the barrel though. Taking a que from Roy Weatherby, I decided to lengthen the throat to allow for more velocity and less pressure. However I didn't want to make the throat so long that accuracy suffers. I measured the bearing surface of the 250 gr LAZER projectile and cut the throat just a hair shorter so the bullet is never unsupported by either the case neck or the rifling but it should allow for more speed. Once everything was together it came time to start working up a load for it.














So far I have only tried 2 powders. One being Reloader 17 and the other being H4350. RL 17 seems to be coming out on top so far with better accuracy and much tighter velocity spread. I started at 56 grains and gradually worked up. The longer throat definitely helped velocity and keep the pressures down without sacrificing accuracy. At 64 grains I started to notice my extreme spreads increased slightly so I called that max. 64 gr of RL17 with the 250 gr LAZER projectile 15 thousandths off the lands netted a whopping average of 2827 fps with an extreme spread of 16 fps. Brass looks perfectly normal with no pressure signs at all. Accuracy is absolutely stellar shooting 3/4 inch and under groups at 200 yards. Recoil is less than my 6.5x55 with full power loads. The Lil Bastard break does a great job of taming down the recoil. You can shoot this gun all day long with no discomfort whatsoever.







All in all I couldn't be more pleased with how this project turned out. As you can see, when you do not limit the case by trying to stuff a nearly 2 inch long bullet down inside it to try to get it to fit in a short action, there is no reason why you cannot match and exceed 338 win mag ballistics. It is nipping at the heals of the 338 lapua burning significantly less powder, fits in a standard sized action, and magazine feeds with vld bullets. Something the bigger 338's cannot do. With a muzzle velocity of nearly 2830 fps, it has an effective hunting range of over 1100 yards with the 250 gr LAZER projectile and for paper punching, it doesn't go subsonic till the 1 mile mark and CE's 252 gr MTH bullet doesn't go subsonic till nearly 2000 yards! All in all it looks like I have a real winner on my hands here. I hope to put it to good use on elk in the next couple of years.
 
This is neat. Well done. I'm going to do some more research on this caliber, very interesting.

Nice Build.
Everyone told me that I probably wouldn't even see 338 win mag speeds but I knew from past experience with the 300 blackout that when you are not limited by coal requirements, these small cases with big bullets can be ramped up quite a bit. I can see why winchester abandoned the idea of a 338 on a short action. Those projectiles are nearly 2 inches long. If they were seated to short action mag length, you would loose a ton of powder capacity. Probably 15 grains worth. Possibly more. Cutting Edge's single feed projectiles are great for maximizing powder capacity. They have a bore rider and a short bearing surface to help get the bullet seated out further and only the band touches the bottom of the rifling to help reduce friction. They really have a great thing going there. Most of my rifles are feed CE bullets. My 22 inch 300 blackout is pushing their 100 gr raptor at 2700 fps with one hole accuracy and my 6.5x55 spits the 110 gr copper raptor at 3150 fps and is also under 3/4 moa. My suggestion is if you do decide on one, keep the factory throat and see where it gets you. If you start running into pressure issues before you hit the velocities you want , then go ahead and lengthen it a bit. Mine is right about .4
 
This is great! So what is a rough overall length on your round? considering doing this in a rem 700.
 
Very cool build! Been trying to get a 338 WSM build of the ground for a couple years but build around the 250 Berger. I'd like to run the Lazers and see how they do on game, I've ran a number of MTH in 6.5 and 338 and was not impressed by the wound channel at range, accuracy was excellent however.
 
Very cool build! Been trying to get a 338 WSM build of the ground for a couple years but build around the 250 Berger. I'd like to run the Lazers and see how they do on game, I've ran a number of MTH in 6.5 and 338 and was not impressed by the wound channel at range, accuracy was excellent however.
I wasn't impressed with the 6.5 mth wound channel either. The fragments from them were tiny. Seems like 30 cal and up they do considerably better. I shot a deer a couple years ago with the 140 mth from my 300 blackout at 2300 fps and they seemed to do ok. Broke one shoulder going in and exited through the ribs. Deer went about 30 yards. I haven't been to impressed with the bergers since they toughened up the jackets in them. Shot 2 deer with my 6.5x55 with the 140 gr berger at 2840 fps. Both were broadside shots under 100 yards and it wasn't until the bullet started to exit the offside of the heart before they expanded. Both deer ran about 75 yards. I wish they just kept the same jacket since the vast majority of us aren't running them through cheytac wildcats. The raptor is a different story and absolutely devistates deer. I shot one one the run with the blackout and hit in the hind quarters and it slowed it to a walk. I put one more in the vitals and it dropped right there. Also shot one at 230 yards with the blackout and the 100 gr raptor through the shoulder and it was drt. I see no reason the copper ones would be any different. The new LAZER projectile is supossed to have better terminal performance than the mth line. I may put it to the test on some hogs this summer.
 
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This is great! So what is a rough overall length on your round? considering doing this in a rem 700.
Overall length for me if I remember correctly is 3.435. That puts me 15 thousandths off the lands in mine. I'll double check that when i get back home. No point in trying anything else as it easily outshoots me. The wyatts extended box mag goes out to 3.7 inches I believe so plenty of room for even 300 grainers but I don't think there's enough boiler room to make the most out of the 300's. You could go with a cross canyon arms short mag case and neck it up to 338. That is essentially an ackley improved short mag case and should get pretty close to RUM level performance. I believe the ratchet rifling is responsible for a bit of the speed as well. If anything, its definately the easiest cleaning barrel I've ever had. 2 or 3 patches and your done.
 
Very nice rifle and thought going into it as well ! I have a couple SA cartridge LA rifles and considered one similar to yours. The 300WM mag is considerably narrower at the shoulder than the WSM I think, so did you have to do any work on the mag lips ? Also do the WSM rounds in the mag slide forward under recoil ? Mine are both .243 LA with brakes so recoil isn't an issue.
Also same experience with the Cutting Edge 6.5 on an antelope, pencil hole thru at 600 yards.
 
Very nice rifle and thought going into it as well ! I have a couple SA cartridge LA rifles and considered one similar to yours. The 300WM mag is considerably narrower at the shoulder than the WSM I think, so did you have to do any work on the mag lips ? Also do the WSM rounds in the mag slide forward under recoil ? Mine are both .243 LA with brakes so recoil isn't an issue.
Also same experience with the Cutting Edge 6.5 on an antelope, pencil hole thru at 600 yards.
I had to bend the feed lips outward slightly to get the cartridges to ride up higher. Due to the wider cartridge, the magazine is far more comfortable holding 4 as opposed to trying to cram 5 in there. The magazine spring is stiff enough and recoil is very mild so the cases don't ride forward under recoil at all. AI mags don't have nearly as strong of a spring so I can't comment on them. I got a bunch of people locally highly interested in having me do a similar setup for them so I might play around with the follower and possibly install some type of polymer guide rail for the shoulder of the case to ride on to prevent them from sliding forward
 
Very cool build! Been trying to get a 338 WSM build of the ground for a couple years but build around the 250 Berger. I'd like to run the Lazers and see how they do on game, I've ran a number of MTH in 6.5 and 338 and was not impressed by the wound channel at range, accuracy was excellent however.
Right now I'm working on some other loads. I was spot on with my guess of 64 gr being max for the 250 lazer. I left the rounds in the car as I was setting up the other day. By the time it came time to start sending rounds downrange, I'd say the temps were 95 to 100. Extreme spread was now over 30 fps and the bolt lift was ever so slightly sticky. 2 finger lift as opposed to one and there was the slightest hint of ejector swipe on some of the brass. So for hot weather it looks like I'm gonna have to back it down slightly with RL17. Its not horribly sensitive but definitely more so than Hodgdon's extreme powders. It still is the go to powder producing velocities far above everything else and very good accuracy as well. So far 60 gr is pushing the 250 gr Berger at 2600 fps with plenty of room for improvement. Also worked up to 70 gr under the 176 gr ER Raptor. Those are running right at about 3300 fps and should be an absolute hammer for deer sized game at all but extreme ranges.

 
Played around with some of the 225 gr MTH bullets today. Only loaded up enough for chrony testing and to shoot one 3 shot group. 65 grains of RL17 netted a hair over 2900 fps with a very tight velocity spread. Accuracy however was only about 1 moa. I'm playing around with the seating depth some. I got batches loaded at .025, .015, off the lands and some seated to just barely touch. I am also going to try a single feed style 225 mth that they no longer produce. I am also trying to see if I can get them to release a single feed style 225 gr lazer. Word is that they are considering it. Would be a great hv load for the larger 338 cases as well.
 
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