Seems like max effective range with the extremely heavy and high BC .416 and .375 and even .50 bullets would be extremely far even when loaded to subsonic levels. Has anyone yet built a rifle and cartridge that was purpose built for this? Given the large bore diameter and decreased powder volume, it could be a very short barrel to achieve max subsonic velocities. You could also design the case by necking up a much smaller cartridge since powder volume would be much less. It would be light, extremely portable, and with a suppressor very very stealthy. For military use, the ammo would still be small enough to be practical for carrying high volume and I an imagine the kind of havoc such a weapon would wreak upon the enemy.
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Purpose built subsonic rifle
- Thread starter ahhshoot
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Yes many have built the .510 whisper , the big brother to the 300 blackout . I have a blackout and building a 510 whisper, just waiting on barrel
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that's exactly what I'm talking about. Looks like I'm a little behind the times. What a cool rifle. Now I want to build one haha.
I've bailed on the 300 whisper stuff and have built a 12.7X48 (510 whisper) and a .338 BR for subs. Both are outstanding and the .338 BR (benchrest) is the first hollywood quiet subsonic round I've encountered. The 510 will run any of the military bullets pulled from the BMG or you can find heavier high BC bullets like the Hornady AMAX or the Lehigh barstock bullets. I like to shoot the reactive bullets like the tracers or the API and APIT. The tracers light up well and the API's flash when you hit hard targets like steel plates.
For the 338 we run the 6mm, 7mm or 30 benchrest cases necked up to .338 and run 300 gr Sierra matchkings. I'm shooting 16 or 17" barrels for both the 338 and the 510 though I know guys who have longer or shorter barrels that work well too. If you don't care about supersonic loadings then no reason to go over 16". On the other hand both the 338 and 510 can be loaded with lighter bullets supersonic and do quite well. The 510 is launching 300 Barnes flat points at about 2300fps so far. I still haven't had a chance to work up a good load for it and I think I might be able to get 2500fps out of these. It would make a great deer rifle here in Indiana where we are limited to 1.8" long cases of .358 cal or larger. The .338 can launch 200gr Hornady SST's at 2300 fps and a friend has been using his rifle for hunting in the woods out west. Deer and elk have fallen to the round.
I shoot my Desert Tactical SRS/Covert with both rounds and normally shoot suppressed. The 510 is based on the .338 Lapua mag case cut down and with a neck turned on it. The .338BR is just the standard Remington Benchrest case necked to .338. If you're shooting subsonic the one issue you'll have is the rainbow like trajectory at longer ranges. The high BC bullets don't lose much velocity but since they're moving so slow they do drop more than the same round at high speed. I've heard of guys shooting these rounds at 1000yds but I think it would be tough to do consistently. I've fired .50 BMG tracer bullets in the 510 out to 1500yds and they do have quite an arc at that range. Might be a good choice for dropping rounds on the far side of walls or other obstacles since they drop so near vertical at that range. In any case it is a great niche to be involved in and its great fun to shoot. Low noise, low recoil, less cost for powder and lots of fun.
First pic is the .338 BR with 200 and 300 gr bullets next to a .308 ball round. Next is the Desert Tactical rifle with the suppressor on the .338 BR barrel (17" bbl). Next is some test .510 rounds using cast gas checked bullets and one round of API 650gr. Next pic is the Desert tactical rifle in 510 with the suppressor prior to swapping the long handguard for the short one.
Frank
For the 338 we run the 6mm, 7mm or 30 benchrest cases necked up to .338 and run 300 gr Sierra matchkings. I'm shooting 16 or 17" barrels for both the 338 and the 510 though I know guys who have longer or shorter barrels that work well too. If you don't care about supersonic loadings then no reason to go over 16". On the other hand both the 338 and 510 can be loaded with lighter bullets supersonic and do quite well. The 510 is launching 300 Barnes flat points at about 2300fps so far. I still haven't had a chance to work up a good load for it and I think I might be able to get 2500fps out of these. It would make a great deer rifle here in Indiana where we are limited to 1.8" long cases of .358 cal or larger. The .338 can launch 200gr Hornady SST's at 2300 fps and a friend has been using his rifle for hunting in the woods out west. Deer and elk have fallen to the round.
I shoot my Desert Tactical SRS/Covert with both rounds and normally shoot suppressed. The 510 is based on the .338 Lapua mag case cut down and with a neck turned on it. The .338BR is just the standard Remington Benchrest case necked to .338. If you're shooting subsonic the one issue you'll have is the rainbow like trajectory at longer ranges. The high BC bullets don't lose much velocity but since they're moving so slow they do drop more than the same round at high speed. I've heard of guys shooting these rounds at 1000yds but I think it would be tough to do consistently. I've fired .50 BMG tracer bullets in the 510 out to 1500yds and they do have quite an arc at that range. Might be a good choice for dropping rounds on the far side of walls or other obstacles since they drop so near vertical at that range. In any case it is a great niche to be involved in and its great fun to shoot. Low noise, low recoil, less cost for powder and lots of fun.
First pic is the .338 BR with 200 and 300 gr bullets next to a .308 ball round. Next is the Desert Tactical rifle with the suppressor on the .338 BR barrel (17" bbl). Next is some test .510 rounds using cast gas checked bullets and one round of API 650gr. Next pic is the Desert tactical rifle in 510 with the suppressor prior to swapping the long handguard for the short one.
Frank
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This ^^^^
I've learned more about subsonic wildcats from Frank than anyone else. One thing I'll add on .510 Whisper is that making brass for the first time can be really, really annoying if you don't have a lathe. The upside is that once you make the brass, it'll last a long time. I'm at the point where if my .338LM brass starts to show wear from too many loadings, it goes into my .510 pile. The same goes for brass with oddball weights on the extreme ends when sorting.
I've learned more about subsonic wildcats from Frank than anyone else. One thing I'll add on .510 Whisper is that making brass for the first time can be really, really annoying if you don't have a lathe. The upside is that once you make the brass, it'll last a long time. I'm at the point where if my .338LM brass starts to show wear from too many loadings, it goes into my .510 pile. The same goes for brass with oddball weights on the extreme ends when sorting.
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Wow, thanks for the wealth of info. I'm glad there's interest in this besides my own. I currently shoot a 338 LM so the .510 might actually be a future possibility. If I were to build one of these,
A) Would I be able to use a standard short action, and if so, where would I obtain a bolt face that would accommodate the 338 case? Are there tips you guys have learned with regards to the best actions that are most easily convertible?
B) What kind of barrel twist would be optimal to stabilize that big .51 at such low velocities with a short bbl?
C) Would I need to source a specific barrel manufacturer to cut the chamber for the .510 whisper?
D) If I don't have a lathe, what would be needed to fully convert a standard 338 LM case to a .510 whisper case?
Thanks to all for the help.
A) Would I be able to use a standard short action, and if so, where would I obtain a bolt face that would accommodate the 338 case? Are there tips you guys have learned with regards to the best actions that are most easily convertible?
B) What kind of barrel twist would be optimal to stabilize that big .51 at such low velocities with a short bbl?
C) Would I need to source a specific barrel manufacturer to cut the chamber for the .510 whisper?
D) If I don't have a lathe, what would be needed to fully convert a standard 338 LM case to a .510 whisper case?
Thanks to all for the help.
458 SOCOM.
I've got 4 rifles chambered in 458 SOCOM with 1-8" twist SS barrels to stabilize 600-700gr projectiles. Some of these bullets are almost 2.5" in length. That's longer than the case! These single feed in Savage Short action rifles using a sled in place of the follower. They use standard commercially available 458 SOCOM cases and dies, nothing fancy to make. I run 16" barrels to avoid SBR but it does not really need more than 10" or so to burn all the powder. Trajectory with the 582gr. Lehigh lathe turned brass projo's is almost EXACTLY that of a 300 Blackout 220SMK load, but with 3x the bullet and a lot more energy. It's really the XXL cousin of the Blackout.
With a can, these are legal for deer in Indiana. The law just changed so I haven't punched one with this yet. Have a possible pig hunt in SC next month so I'll know more then if it works out.
I've got 4 rifles chambered in 458 SOCOM with 1-8" twist SS barrels to stabilize 600-700gr projectiles. Some of these bullets are almost 2.5" in length. That's longer than the case! These single feed in Savage Short action rifles using a sled in place of the follower. They use standard commercially available 458 SOCOM cases and dies, nothing fancy to make. I run 16" barrels to avoid SBR but it does not really need more than 10" or so to burn all the powder. Trajectory with the 582gr. Lehigh lathe turned brass projo's is almost EXACTLY that of a 300 Blackout 220SMK load, but with 3x the bullet and a lot more energy. It's really the XXL cousin of the Blackout.
With a can, these are legal for deer in Indiana. The law just changed so I haven't punched one with this yet. Have a possible pig hunt in SC next month so I'll know more then if it works out.
My .510 is using a 1:9 twist barrel. The more common .50BMG destined barrels tend to use 1:15, which will likely not be enough to stabilize subsonic bullets. As for making brass without a lathe, it's annoying but doable. Here's what I started with:
1. pipe cutter to rough trim the brass
2. .50BMG trimmer to trim to actual trim length
3. custom pilot (about 1mm under .50BMG pilot) for neck turner and very methodically turn the neck down the proper distance and depth
4. run through CH4D expander and sizer dies
I made 10 cases that way then basically gave up and had my gunsmith make another 20 cases in his lathe in no time.
1. pipe cutter to rough trim the brass
2. .50BMG trimmer to trim to actual trim length
3. custom pilot (about 1mm under .50BMG pilot) for neck turner and very methodically turn the neck down the proper distance and depth
4. run through CH4D expander and sizer dies
I made 10 cases that way then basically gave up and had my gunsmith make another 20 cases in his lathe in no time.
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I'll try to answer these in order.....
No you can't use a short action...unless you intend to only shoot 300-450gr bullets seated deep. With .50 BMG bullets the overall length is close to the .338LM. Opening up the bolt face is possible but you're better off using an action intended for the right round-ie .338 lapua mag or 416 rigby. I've built 4 rifles using CZ550 Safari Mag actions and they work well.With BMG bullets they will hold 3 in the mag and feed perfectly. If you want to shoot short bullets you need to make up a spring for the front end of the follower to make it feed right. You can also get actions from most of the "clone" makers like Stiller, Defiance suitable for the .338LM. The desert tactical is ideal since you simply swap bolts or bolt heads depending on when it was made and the barrel change takes about a minute.
Dogtown hit it on the head with barrels. You need a 1-9 twist for the subbies.
I don't know of anyone who makes barrels and will chamber for the 510. I normally get my blanks from PacNor. They make good blanks and are one of the few who does the faster twist in this bore. I use stainless because suppressors are traps for moisture and if you don't oil when you're done shooting you can trash a barrel with rust. One other note here related to the barrel is that the name Whisper has been trademarked by JD Jones. This means guys can't make you a 510 whisper barrel so you'll have to go with the alternative 12.7X48 or buy direct from JD Jones. He won't make you a barrel only, its the whole shebang or nothing. There are other gunsmiths and makers out there who can do your chamber but they'll need the gun to insure headspace is correct.
Dogtown nailed the hand method of making brass too. Its pretty much how I make it but I use the lathe to turn the cases for me. I've not had much luck with cutting the necks on the lathe and the neck turner is very consistent. Trim the case to near length with a chop saw, hack saw or pipe cutter. Trim the case to length with a case trimmer. Run the case through the sizer to squeeze the neck down. Run the expander to open the neck up internally to just undersize but with no internal taper. Use the neck turner to turn the neck and shoulder. It may take 2 or more runs at this since you're cutting about 10-15 thou off the necks. Make sure you trim the case to length prior to the last neck turn. The neck turner indexes off the case mouth and since your shoulder is cut by the neck turner you want to make sure its right. Your headspace is set by this so make it correct. CH4D makes dies with the expander. I'm not sure who else makes dies.
I love my 510 and its great fun to shoot but the 338BR is by far the easiest to make brass for and a much better one to start with. You can use any short action with the same case head diameter as the 308. No special fixtures or anything for making brass. CH4D has dies for this one too. Bullets are out there and have been pretty easy to find in this odd market. The rifle will be lighter and so will the suppressor. The initial cost will be lower for both the rifle and the ammo.
Hope that helps
Frank
I run a 338 Federal and 510 Battleship in subsonic form. And with the advancements in bullets it is a super fun way to go. The 510 Battleship was designed by George Gardner at GAP. It is 416 Rigby brass cut down and loaded with the 50BMG bullet.
Both rifles run a 16" barrel and have the appropriate suppressors on them. The battleship is super heavy but my suppressor is 5lbs. I like them both, very fun to shoot. The 338 Federal has taken out more skunks and groundhogs then I can count.
Check into Lehigh controlled fracturing rounds.
Both rifles run a 16" barrel and have the appropriate suppressors on them. The battleship is super heavy but my suppressor is 5lbs. I like them both, very fun to shoot. The 338 Federal has taken out more skunks and groundhogs then I can count.
Check into Lehigh controlled fracturing rounds.
Thank you very much Frank & co, this is opening up a whole 'nuther world of shooting for me. I don't know if that's good or bad, but I like it. Very awesome guns as well. It does sound like the 458 Socom is the way to go if I don't have a lathe. Savage action won't be hard to get.
Wicked Weapons, who made your 458 Socom tube?
Wicked Weapons, who made your 458 Socom tube?
What sort of effect are you looking for? I've fired it at 270yds with good accuracy and frequently shoot at 300 with a likelyhood of first round hits. I've shot it at a couple shoots in wyoming at ranges out to 1000yds but its tough to hit first shot with it til you get some info worked up. I've heard of guys hitting things on purpose at ranges out to 1000yds pretty consistently but the trajectory is rainbow like so range estimation is very important. At 1000yds with an initial velocity of 1050 fps the hornady 750gr AMAX shows a velocity of 879 fps and an energy of 1288 ft/lb according to JBM ballistics calculator. This tells me the bullet is plenty capable of killing or maiming even at that range. According to the same calculator the drop at 1000 is 1637.9 inches with a time of flight of 3.155 sec. This is all using a 100yd zero.
I've hit steel targets (large ones) at 800-1000 yds with API and they flash when they hit. It takes quite a bit of energy to pop the incindiarys so they're still hot at that range. Not sure if that is the info you want or not....
Frank
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Yeah, realistically the .510 has a bit more effective range over other subs, but all subs in general tend to work best inside of 300m. Beyond that you start to hit a wall with elevation and accuracy overall as the bullet lacks the energy to fight gravity, drag and wind anywhere near as effectively as when supersonic.
Hey KYS, whats the info on a 338Federal in subsonic? I have 338Federal, Tikka T3, what kind of load do you use?
Custom 16" barrel to run the subs. Load info belongs to Copper Creek, you would have to ask them!
biffj, That's wild. I was just curious as I haven't really ventured into this niche too far. My experience is limited to some subsonic .308's from an SR25 and the farthest we could reliably shoot without having to do some crazy kentucky windage was 300m but the accuracy did seem to be fairly repeatable. I have 6.5 Creedmoor on order from Accurate Ordnance and just for shits and grins I may try to spin up some subsonic loads for it, but I realize that it's not the best platform. Thanks for the info
One big issue with using full sized cases to shoot subs is twist rate and bullet weights. With a 308 running a 1-12 twist you can't reasonably go any larger than the 190gr spitzers or boattail spitzers without having stability problems. Using 1-10 twist you can go with 220gr round nose but 200-210gr is getting into the possible damage to the can issues. We run 1-8 twist for subs in the 30-221/300 fireball/300 whisper/300 blackout(all the same round, different names for trademark purposes). I've done repairs on a number of suppressors used by guys who didn't know about stability and twist rates. Some got trashed pretty bad. It doesn't take a lot of wobbling to hit a baffle and things get worse from there. The same is true of the 338. Using the 338 federal cases you are limited to bullet weights and powders that take up a lot of space in order to get any semblance of accuracy. The whole point of subsonics is to maintain the highest energy levels possible while reducing noise. If you can be shooting 240gr bullets why would you fool with 180's? If you can shoot 300's in the 338 why fiddle with 210's or 220's. You're wasting time and energy when you could be using a more efficient platform using less powder and heavier bullets. This is the reason the blackout and whispers have done so well. They have enough powder space but no too much. You don't have to worry about tapping the powder down to the bottom of the case each time to insure consistent ignition and accuracy. You can use a much wider range of powders instead of being limited to stuff like Trailboss just to fill the case. This gives you a lot more room for finding an accurate setup in your rifle. If you're not shooting with a suppressor what is the point of shooting subs?
just a few thoughts to keep things headed in the right direction. If you are just looking for quiet gallery type rounds to shoot from your favorite long range target rifle try making up wax bullets and using just the primer to propel them. They're good for 25-50 yards in most cases and very quiet.
Frank
just a few thoughts to keep things headed in the right direction. If you are just looking for quiet gallery type rounds to shoot from your favorite long range target rifle try making up wax bullets and using just the primer to propel them. They're good for 25-50 yards in most cases and very quiet.
Frank
What kind of suppressor do you run on your 338? Seems like the ones designed for the 338 LM are too big/expensive and those designed for the .308 would work well except for bullet diameter. I have a couple of 338 Feds (Ruger M77, DPMS LR-338) and have thought they would make good hosts as well as potentially rebarreling a .243 Savage Striker to a faster twist than the others.
Have any of you guys tried the 30BR as a subsonic round? I've kicked that one around along with a 7.62x39mm with a .308" bore, I'm not sure that either one buys you anything that a 1:8" twist .308win won't do.
30 BR has the same issue the 7.62X 39 does..too much case capacity for the job. With the max bullet weight being 240 gr in jacketed types you've got too much room and not enough powder to take it up. Neck the thing up to .338 and it gets very good. Thats the .338BR I alluded to previously. I'm using 13gr of 2400 or 4227 to propel a 300 gr Sierra matchking at 1050 fps. Ultra quiet and very hard hitting. With the .338 you're taking up more room with the bullet and needing just a bit more powder to launch it so you have used up more case capacity and it makes powder position less critical. When you have just a little powder in the case you need to make sure you always settle it in the same position. Some guys tip up the barrel and tap it to settle powder...some have other little dances. If you fill the case more you don't need to do that. If you want a 30 cal subsonic go with the whisper/blackout/fireball etc. Cheaper brass than the BR and factory made rifles out there.
Frank
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