.308 subsonic load development.

Hey chaps I started to have a play with subsonic rounds yesterday.
200gn flat nose lead cast projectiles
Started at 10.5gn of trailboss and worked down to 10.2gn.
Magnum primers.
So at 10.5gn I was still getting 1215fps and at 10.2gn 1120fps. Will have to go lower I'm expecting that it will be 9.9gn-10gn.
I fired 12 rounds and the recoil was bugger all. The best grouping was with the 10.2gn at 50meters. Only issue I noticed was the amount of lead fouling in my barrel.
Here is the group of 10.2gn and a little video to show recoil and sound.
Cheers. http://uploads.tapatalk-cdn.com/2016...e8dff1fa65.jpghttps://vimeo.com/197216818


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You need to load between 8.0 grs and 8.5 grs to get down to 1050fps and don't use magnum primers they are way to hot for Trail Boss,
and get all the copper fouling out of the barrel cast bullets don't like copper even a little bit it will pull lead off the bullet and deposit in the barrel

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Originally Posted by shooternz

You need to load between 8.0 grs and 8.5 grs to get down to 1050fps and don't use magnum primers they are way to hot for Trail Boss,
and get all the copper fouling out of the barrel cast bullets don't like copper even a little bit it will pull lead off the bullet and deposit in the barrel

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I got my projectiles from a guy in tokoroa rob is his name. That's not you by any chance?:-)


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Yep that's me, Thanks for trying my bullets let me know if I can help, the 151HP's are the better bullet don't really need the extra 50 grains, customers have shot goats pigs and deer with them
not many recovered bullets usually they are through and through, it may take a few rounds for the barrel to settle down if you keep shooting lead it will polish the barrel like a mirror
and will never wear out with the light loads, you can easily push gas checked bullets to over 2000fps but it is very technical getting there much less drama keeping to 1800-1900 fps or less,
Have fun it's a buzz getting small groups with cast bullets,
Cheers
Robert.

Attachment 61308

thems good alright

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Originally Posted by shooternz

Yep that's me, Thanks for trying my bullets let me know if I can help, the 151HP's are the better bullet don't really need the extra 50 grains, customers have shot goats pigs and deer with them
not many recovered bullets usually they are through and through, it may take a few rounds for the barrel to settle down if you keep shooting lead it will polish the barrel like a mirror
and will never wear out with the light loads, you can easily push gas checked bullets to over 2000fps but it is very technical getting there much less drama keeping to 1800-1900 fps or less,
Have fun it's a buzz getting small groups with cast bullets,
Cheers
Robert.

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I have your 150gn hp and I have your 186gn as well. You sent me a couple other samples too. Will get into them in the next couple days.


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Originally Posted by Micky Duck

Attachment 61308

thems good alright

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How fast have you got them going micky duck?


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somewhere AROUND the speed of sound....4.1 grns trailboss in x39mm case std primer.
I was usung 7 grns but have kept dropping to try to get subsonic without use of chrony...they arent hear the hammer drop hushed but that could be my tired spartan with 10mm exit hole too.... lets just say you dont hear stuff all if you arent the one squeezing trigger.

What's the accuracy like? the 150hp's are really a little under size for the 7.62x39, they were designed for the .308 so it is hard to make them much over .309" I guess at sub sonic speed it's not a problem
upping the velocity could be tricky.

well any bunnies under 50 yards are in trouble..... sounds like I need to go shoot a group to find out LOL
one thing I keep forgeting to mention .... when resizing cases I only ever use the .308 rod/ball/insert the lee dies came with both .308 and .311 and since we use .308 pills thats the one we use.
guess it helps heaps with holding projectile steady and giving it a good start off.
with 125 nosler ballistic tips rifle holds to under 3" at hundred,bought some SST hornady loads but Ive been too tight to shoot them at paper....
photo doesnt show it well but rifling marks are good and deep,with well defined edges so they must be fat enough/barrel tight enough.

with subsonics as in anything you need to ask yourself how far do i want to go . . . if its 50yds then you wont have a problem

if its 100, 200, 300 or further ( which are achievable ) you'll need to put time and money into it . . . that goes double or more for cast

whatever you decide I'm sure you'll have fun, they are addictive . . . good luck

R.

I have achieved what I set out to do
a quiet load that is great for bunnies or my house muttons with more authority than the humble .22lr
I can take possum out of tree while out hunting and not disturb the whole neighbourhood.
and its a load of fun
wallaby at 100 yards would be the futherest I would be interestd in pushing them....again just for grins n giggles.

i shot this 3 inch group this evening at a paced 250yds (forgot my rangefinder ) letting the bullet drift with the wind. Strelok predicted .5mil which was pritty close.
rifle was a .308 using cast 197grn. RCBS bullets at 1070fps
Attachment 61365
keep in mind at that range if your out by 5yards bullet drop will be + or - 3 or 4 inches

[QUOTE=shooternz;549546]Yep that's me, Thanks for trying my bullets let me know if I can help, the 151HP's are the better bullet don't really need the extra 50 grains, customers have shot goats pigs and deer with them
not many recovered bullets usually they are through and through, it may take a few rounds for the barrel to settle down if you keep shooting lead it will polish the barrel like a mirror
and will never wear out with the light loads, you can easily push gas checked bullets to over 2000fps but it is very technical getting there much less drama keeping to 1800


I just ordered some of these from you Robert. Thanks for the informative replies on TM. Very helpful.

Thanks for the order, I need the cash

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Originally Posted by shooternz

Thanks for the order, I need the cash

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I had best pay for them right now then :(

No rush I have plenty of baked beans to celebrate New Year with, I can't post them until Wednesday,
Have a great New Year:beer:

Anyone bother drilling out their primer flash holes for subsonic loads?

nope and I dont use magnum primers anymore either...trail boss goes off with a bang without alterations.

Don't do it all you do is stuff up your cases none of the powders used for subsonic loads require drilled primer holes or any other silly mods Magnum primers are way to hot for subsonic loads,
If you are using shotgun and fast pistol powders Dacron fibres as a filler are some times necessary to hold the powder against the back of the case, It is a no no with Trail Boss in a .308 case 8.0 to 8.5 grains
will give you around 1050fps the most I have tried was 12.0 grs accuracy went from 1/2" group to 5" at 50 metres.

I haven't played with this for years but when I did my experiance was the same - don't bother with drilling primer holes or magnum primers. The problem I had was the big pills didn't stabalise that well at subsonic speeds in the 308 barrel twist rate and the light pills took a worringly small amount of trail boss to get down to subsonic speeds. 95g Hornady XTP in 30 cal (outdoor supplies have them) is a great projectile thats designed to expand at those speeds being a pistol projectile but it was down around a half full case which made me worry about detonation so I think you are better off with the cast projectiles.

My current plan is to build a 9MM AR15 and then load them down a bit to get subsonics.

I re visited my subsonic loads today. Using 150gn hollow points. 8 grains trail boss gives me 1078fps average. They group well at 50meters.
This is my 3year old son shooting them this afternoon. No recoil and about same noise as a 22lr.


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I just brought some to try in my new bergara single shot. Really keen to get the kids into it and this will make it easier. Will post up results when we shoot a few deer with them

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Originally Posted by Manu

I re visited my subsonic loads today. Using 150gn hollow points. 8 grains trail boss gives me 1078fps average. They group well at 50meters.
This is my 3year old son shooting them this afternoon. No recoil and about same noise as a 22lr.


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Was there meant to be a video here mate?

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Originally Posted by Gibo

Was there meant to be a video here mate?

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Shit yeah there was.


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Any advise on how to upload video?


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Quote:

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Originally Posted by Manu

Any advise on how to upload video?


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I think you can attach a short one useing tapatalk or otherwise upload to utube/v emo etc and share link.

https://youtu.be/AvB0kmqckvo


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I got all keen reading this so brought some cast bullets from Robert and loaded them up (8.5gr Trail Boss). Was originally intending to smoke a goat just to test terminal performance but opportunities didn't line up. Instead headed to a DOC block th is morning, walked in in the dark and daylight saw me stalking a likely area. Got onto a young red spiker at about 40m, body shot (read: a bit far back) and the moose was down within about 10 m, finishing shot to the swede from 4m and it was all over.
Overall very happy with the cast projectiles, given a sensible range and shot placement they are good to go. Well mushroomed projectile, will upload pic tomorrow.

Attachment 72154

mate you cant complain about expansion like that!!!!!!
keep up the great work Robert...you da man...

Yep, as suggested by @tikka on the 300 blk thread, 50m probably a sensible range to stick to. Around here that is a long shot. Expansion and terminal performance was great. Granted not the best shot I have ever made, but I have had deer go a hell of alot further with full power rounds. Thanks Robert, will use these with confidence.

Thanks guy's makes getting frostbite worthwhile making the latest batch

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Originally Posted by shooternz

Thanks guy's makes getting frostbite worthwhile making the latest batch

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Would they still shoot ok out of a .312 bore?

hell yes...and Robert can size them a tad bigger too.
thems what I use in my x39mm

Yes they seem to shoot ok at sub velocity I wouldn't try them faster would more than likely strip, I can get them to.3105" and they are soft so will obturate up a little.

Went down this track loading up some 220gr freight-trains, had a couple jam in the barrel trying to get load subsonic and decided it was more a theoretical exercise than really achieving much practically. Massive Attack is onto it, using say a dedicated AR with say 147 xtps would be quite handy or some of the 45 cals but harder to import bits/brass etc. The 300blk has shown promise with the Leigh bullets otherwise is a plinking cartridge subsonic

I have worked down from 10gr of trail boss to 7.4gr to get to 1050fps in my 18" Bergara 308 using Roberts cast 151 hp's.
I have read that 70% of max charge is the recommended minimum charge. 7.4gr is about 55%. Although I've not had any issues, should I be worried?

BTW have been using these projectiles in my blackout with 3.6gr Trailboss with great results. They mushroom well and not much runs away. Single shots are great, easy to pick and choose between sub and super where and when required.

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Originally Posted by Muddyundy

I have worked down from 10gr of trail boss to 7.4gr to get to 1050fps in my 18" Bergara 308 using Roberts cast 151 hp's.
I have read that 70% of max charge is the recommended minimum charge. 7.4gr is about 55%. Although I've not had any issues, should I be worried?

BTW have been using these projectiles in my blackout with 3.6gr Trailboss with great results. They mushroom well and not much runs away. Single shots are great, easy to pick and choose between sub and super where and when required.

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I use 7.8 gr of trailboss behind the same projectile out of my 16 inch mod 7 308 and they are good as gold. Only taken a few smaller goats within 50 yards so far, but that is really what I loaded them for.
Another plus, is that my mates 6 yr old can shoot the rifle with ease.