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 Post subject: 308 subsonic loads for 5R
PostPosted: Tue Mar 06, 2012 2:10 pm 
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Silent Operator
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I'm shooting a Remington 5R 20"tube 11.25 twist. This set up is extremely accurate shooting sub min at 100 yrd with 168 BTHP of Sierra and Berger bullets. I am now trying to develop a subsonic loading for the new can I have ordered. Any ideas or experience regarding this twist rate / barrel length? Much appreciated.......


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Fri Mar 09, 2012 7:53 am 
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Silent But Deadly
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I have just stared on this venture my self but one thing I have found is the 168's ar no good. You really have to get into a little heavier bullet. I bought the Lapua 200 gr. Subsonic only bullet and they are just cool to say the least. They are designed to stay stable at subsonic speeds. And Graph and son's had them on sale. Your 11.25 twist will handle a bullet up 220 gr. but I found they drop like a rock at 100y with 10.5 grains of Trail boss. I have been hitting a 35% IPSC popper at 200 yd with the 200gr subs with 10.5TB with good constancy. My M24 has to be dialed to 10.7 on the M3ultra plus I hold one Mil high and that has a center hit.

But you will have to figure your hold over for your distance. But if you can reload your ammo to go 1050 fps at a 100yd you should only have to hold 7.6 MOA high to get a hit with the 200gr.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Fri Mar 09, 2012 9:13 am 
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Silent Operator
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I heard a lot of successful results using Trail boss and I believe that's the way to go as far as powder is concerned. I appreciate your input on bullet weight etc. that is very helpful in my quest for developing a 308 sub load. Thank you...


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Sat Mar 10, 2012 12:08 am 
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Silent But Deadly

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i had very good results (1-1.5 MOA accuracy, no stabilization problems) with 168gr hdy BTHP and 10.gr trail boss in a savage 20" 1:10 bolt gun. haven't shot them suppressed as threading problems on that barrel prevent mounting the can (well, prevent mounting the can without baffle strikes) but unsuppressed they were very accurate and sounded more or less like a .22 rimfire :)


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 6:30 am 
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Silent But Deadly
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Well with 10.5 gr it will sound like a .22 rim fire because it is probably breaking the sound barrier. I cronoed that load and it is any where between 1085 1124 and its loud in the quest for subsonic. I found last night that in a 18" 1-10 .308 that 10.8 gr of trailboss with yield 1050 av with the Lapua sub bullet And if you can find a 180 RN 10.5 will yield about 1020 to 1045 av. If you have to shoot the 168 I would be in the9.7to 10g range but BE CAREFUL CHECK AFTER EACH ROUND to make sure they have left the barrel.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 6:50 am 
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Silent But Deadly
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Forgot to mention DON'T use MAG primers or Match with the match its a waste of money and the mag's will be louder. My test set up is in a closed room and for some reason even with a reduced load the mag primer resulted in a louder load. I don't have the 10000$ sound testing equipment to prove it but I did have 4 people claim the same result. I also drill out the flash hole a little to make sure I get proper ignition.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 10:00 am 
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Wow...In my attempt to drill the flash holes 9/64 with several bits on a 308 Lapua casing has been real tough to drill, I guess I'll have to invest in a drill press. I picked up a box of Laupa 200 gr subs and I'm still researching what kind of powder Vihtavuori uses in their loaded subs. I have been reloading a verity of rifle calibers for over 25 years so this sub stuff is a new challenge but one worth not taking chances with unless it is certain regarding safety not to mention baffle strikes etc. I have spent hours on the net reading everything regarding this subject and found there are just too many pro's and cons, leaving me to believe there are a lot of us out there rolling dice. Many thanks to those who are answering questions so that all of us can continue learning.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 10:27 am 
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Silent But Deadly
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The 9\16 is not what I use I just slightly go larger. Vihta Vuori N310 is the fastest of the brand. VERY HARD TO FIND WHERE I AM. What ever they are using is clean and quiet. I bought 500 rds of the factory stuff and only shoot it once and while but it is superior by far. Graph&son's had it on sale lately.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 1:17 pm 
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Did you ever measure the AOL of Laupa subs, pull the bullet weigh the powder etc. I'd even go so far as to get an independent lab to evaluate the powder. Find that info and you've found the Holy Grail!


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 1:31 pm 
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Silent But Deadly
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Yes its 10g of something resembling n320 but I can't be sure. It is not N310 to small. It is probably another special only Lapua can have powder just like all the other ones. But they metered 10g +- .2g I work were there is such a lab but explosive powder would be a fast ticket to unemployed line LOL


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 12, 2012 2:59 pm 
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I have buddy who's friend hunts with a suppressed 308 in England...yes England UK and he bought his suppressor in a local sport shop with no paper work, no special tax, no nothing! it is totally legal to purchase and use a suppressor in England as it is to own and operate a skill saw in the USA. No questions asked. I will contact him for info regarding this subject. That powder is widely used in Europe. How dense was the powder you found Laupa's subs and how much of the case did it take up? what was the AOL????


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 13, 2012 6:27 am 
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Silent But Deadly
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Yes, there it is considered RUDE not to hunt without a suppressor. And most of the world views them as England. Have you ever tried to get a gun there? You have to be patient and you have to be willing to jump thru allot of hoops. I think if it is a center fire you have to store it with the police unless you own land of some size and can keep it for animal control. South Africa has the same policy regarding suppressors they use that powder there also I will call one of my contacts there and see as well. I think last time I checked he was still shooting competition there, they have IPSC matches there.

I am hearing N320 allot it seems to fill the case a little more than N310 and it is the second fastest powder I ordered both yesterday.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 13, 2012 9:04 am 
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Yes that's correct about gun ownership in England, this fellow works as an engraver for Holland & Holland. I'm curious what he shoots for ammo and what he can suggest for reloads in 308 cal. When I hear something I'll let you know....until then I'll keep beating the bushes for answers.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 13, 2012 9:57 am 
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I came upon some interesting reading....

The powders of choice have been the time-honored Unique and a powder made in Finland by Vihtavuori Oy called N 310. The Germans developed a very fast powder for their suppressed rifles during World War II, and this may be a very close duplicate of that powder. It should be mentioned that the Finns turned some of their subsonic rifle bullets backwards for better accuracy and improved terminal performance. They also developed a system using a few drops of solvent to dissolve the upper layer of their fast powder. After this solvent evaporated, the powder was thus sealed into the rear of large-volume cartridge cases. A bullet was then seated and heavily crimped in place. This helped to achieve better combustion and improved uniformity. Prior to this a filler, such as nitrated cotton fiber or kapok, had been used on large-volume shells. The solvent was a stroke of genius because it rapidly evaporated, did the job very effectively, and left nothing extra inside their suppressors.

Interestingly, we were using N 310 powder in a Thompson Contender, which developed the disconcerting habit of opening up by itself each time it was fired. Curiously, no damage occurred, and the bullets hit the target as though nothing was amiss. The standard pistol primers did not indicate any sign of high pressure. The velocity was 300 m/s or 1,000 fps, out of a 21 inch, unported barrel. After this happened several times in a row we switched to Unique (a slower powder) and the problem went away.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 13, 2012 10:07 am 
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Silent But Deadly
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That is interesting. I have read about the CAT SNEEZE rounds also that use filler. But one thing is crimp is bad for low velocity and the accuracy. I'm sure they were not shooting at 200yds. Now I did hear of lathe turned brass with a reduced capacity chamber but very hard to get and 10$ a piece. The brass is specially designed to with stand multiple loading up to 100 times if memory serves.

I would not mind using a filler on one of my .308 suppressors because I can take it apart and clean it but my AAC's I would not.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 13, 2012 3:36 pm 
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That's understandable. I don't believe in using fillers as I also will be using an AAC can.
And the beat goes on.....


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 19, 2012 9:52 pm 
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Let me know how that N320 works for you. Thanks :P


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 20, 2012 6:23 am 
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Silent But Deadly
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Still waiting on it. They are slow :lol:


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 20, 2012 8:35 am 
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Silent Operator
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I understand.....I'm still waiting to hear from across the pond,I may have to hire Indiana Jones to find that Holy Grail :wink:


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 20, 2012 12:36 pm 
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Silent But Deadly
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I am going to test 3n37 this weekend I will post results.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Tue Mar 20, 2012 1:08 pm 
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[b]Best of luck with that. Hope it's a good one.....[/b] :wink:


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 26, 2012 7:44 am 
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Silent But Deadly
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3n37 to fine not enough to fill more than 30% case capacity. And to much variance in FPS from the powder being against the primer to against the bullet. It did burn clean. 8.4g against the primer got 1024 but as soon as you lowered the rifle 1005 to 1060, 1080,1000 it was all over the place NOT SAFE !!!!. I don't want to have to worry about were I carry my rifle and how.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Mon Mar 26, 2012 10:53 am 
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Silent Operator
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I was hoping to hear better news from your results....I spoke to my buddy across the pond and he said he shoots standard velocity loads now but in his first experience with a can, he started off casting his own bullets ( for economical reasons) and eventually that got old. I told him what I was after regarding Vihtavuori sub loads he stated, That was the powder manufacture he used however he had no info on their 200 gr.sub loadings. He 's got his ear to the ground and will research that info for me and as soon as I get anything back I'll let you know. I suspect part of Vihtavuori formula for subs are keeping that powder N310 N320 or? solidified by dropping some either or acetone into the casing therefore creating a solid pellet of powder that will not shift away from the flash hole when casing is loaded or shifted in anyway.....If this theory holds any water I will let you know. :twisted:


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Fri Mar 30, 2012 10:56 am 
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Silent But Deadly
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Boy, am I getting impatient NO POWDER YET!!!!!! I am going to call another company today and see if they will rush me some out and i have a large gun show here this month.


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 Post subject: Re: 308 subsonic loads for 5R
PostPosted: Fri Mar 30, 2012 12:44 pm 
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Silent Operator
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I'm going to the Orlando gun show tomorrow have friends there who are dealers also class 3 etc. Well... the jury is still out on that Vita powder but I'm also looking into Corbon's 185 gr subs as well. Going to buy a box and dissect a rd or two Check out the flash hole and see if it has been drilled along with weighing the powder etc. I will find out what makes a commercial sub tick!! Keep you posted....good luck at the show.... :wink:


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