30-06 sub sonic

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dieselten
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30-06 sub sonic

Post by dieselten »

does anyone have any recipes for 30-06 subsonic?

Thanks
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Post by jandbj »

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JohnInNH
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30-06 case is to big.

Post by JohnInNH »

The 30-06 would probably have a 1:10 twist so a 170-180 gr flat base round nose bullet would stabilize OK. The issue is the case is huge! If you have a 308 I would use that as the case if you have a 1:10 twist in a 308 hat is even better.

A 30-06 holds 70.6 gr of H2O and a 308 holds 58.9 gr of H2O Figure you will only be using 40% or less of the space in a 30-06. Compare that to 0ver 45% usage in the 308.

Trail boss has a density of .328 g/cc so a load of 9 gr in a 30-06 case would only fill 39% of the case.

8.8 gr of trail boss in a 308 with a 150 gr bullet (flat base round nose) will fill 46% of the case. It will be stable in a 1:12 and 1:10. and is subsonic.

Even that load density will cause less than stellar performance with a fairly wide range in velocity

In Winchester brass using Winchester primers 8.8 gr of Trail boss with the 150 gr Hornady 30-30 bullet gave me average vel of 961 Extreme spread of 77 fps and a SD of 30 in a 1:11.25 twist in a 22" barrel.

Next step is to go up to a 170 gr 30-30 bullet and seat it deeper to take up more case space. I suspect it will give me a better pressure curve and better more consistent velocity.


For the 30-06 I would start by using 170-180 gr 30-30 bullets (flat base round nose) Use Trail boss powder... and try 10-11 grains to start. It will probably be super sonic. Cut back .5 gr at a time till you get close then change .2 gr at a time. Target 1025-1050 FPS.

Once you get close to that... Shoot 2 or 3 5 shot strings over your chronograph and see what your #'s are. While doing that set the target up at 25 feet. check to see if your holes are nice and even. If you are sure the load is stable then use your silencer.

1100 fps is the most unstable velocity.

The 150 gr bullet out of a 1:12 has a Stability factor of 2 at 1100 fps. 1.25 is all you need.

A 168 gr SMK at 1750 fps just gets to the 1.26 stability factor. At 1100 fps it is only .68 and is very unstable. While at 800 fps it is at a stability factor of 1.04 and is considered "Marginal"

While a 180 gr flat base round nose bullet at 1100 fps in a 1:12 twist has a stability factor of 1.64 so it more than stable at sub sonic speeds in a 1:10 and 1:12 twists.

Getting a stable bullet is not the problem it's the large case capacity and the problems that causes. Trail Boss powder is light and fluffy so it will fill more of the case but STILL it is really not enough for a good burn.

I would consider the 308 case the largest I would try and use for subsonic loads. I am sure the 30-06 can work but getting it to be accurate it the problem.
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Rikky Lee
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Post by Rikky Lee »

After spending a long time, a great deal of money and a lot of frustration with the 30BR - I agree, the 30-06 is too big for a 30 cal success story for all the details listed above (good work).
dieselten
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Post by dieselten »

thanks JohninNH, very informative. My rifle is a single shot 20" 1-10 twist. I will be using 180 flat base bullets & Trail Boss powder. I use 9 grains TB with 150 grain bullet in a .308 (M1A). I know the 30-06 requires more powder for the same weight bullet and even more powder again to get a heavier bullet to the same velocity. I will start with 12 grains Trail Boss.

Thanks!
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Post by Artful »

You can try but this can be very fustrating as every rifle is a law unto itself and you may have to adjust you load depending upon temp and elevation changes.
Here's some reading for you.
http://members.shaw.ca/cronhelm/DevelopSubsonic.html

http://www.leverguns.com/articles/paco/ ... harges.htm

http://www.jamescalhoon.com/

There was a reduced capacity aluminum case made by a canadian company went by Stealth Round brand name back in 2007 - sold you cases special dies and information for loading in their special cases.

example
WARNING for STEALTH ROUND Cases ONLY
.308 Winchester with 24" barrel @ 2200' elev.
15.7 grains of Winchester 748. C.O.L. max.2.800"
165-175 grain boat-tails. Standard rifle primer is used.
Produces approx. 1030 feet per second.
I don't seem to find them with a google search and the link I had to them is dead - as I recall the caees were about $15 each. You could try using clean new cases , fluxing the insides and filling up with Lead and drilling out a reduced cavity for sub-sonic uses. That was my next homemade step before David at Liberty suppressos took pity on an old 308 shooter and made up some brass reduced capacity cases.
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Post by JohnInNH »

OK .. You guys got me started.

I went out and got some 170 gr RN FB bullets.

I upped my charge to 8.9 gr Trail boss.

150 gr & 170 gr bullet

941 fps --- 866 fps
964 --- 875
923 --- 844
1008 --- 919
998 --- 902

AV=967 --- av= 881
ES= 84 --- es=75
SD=36 --- Sd= 29

The heavier bullet looks promising...

I ran back and loaded some new rounds

150gr -- 170 gr Bullets

9.2 gr -- 9.5 gr Trail Boss

1042 FPS - NA (leads backwards)
988 -- NA
1002 -- 965
1000 -- 957
886 ERR 930

Av=983 Av=951
SD 58 ES=35
es= 156 sd= NA


The 170 gr bullet looks good... I will bump it to 10 gr Trail Boss next time I load some more.
The 150 I will bump to 9.3 gr but I may get Super/Trans sonic "flyers." so the max may be 9.3 gr.

The 170 gr bullet is getting better/consistent pressures.

At a load of 9.5 gr we are at 50% full
At 10 gr trail boss we are at 53% full.

I don't have enough time to do another trip to my press and range before I loose light.

Maybe tomorrow I will have the best loads for the 308 using trail boss and the 170 gr and 150 gr bullets.

I suspect the 170 will be my keeper sub-sonic round till I get my whisper built.
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Post by johndoe3 »

I use 10.9gr of Trailboss in 308 for 175 and 180gr bullets. So I would imagine the 30-06 needs more powder than that for 180gr bullets. I use 13.5 gr of Trailboss for 220gr SMK in 308 and I load them with a very small jump to the lands. I have never had a 220 gr SMK keyhole at 100 yards with 1 in 10 twist in my 308 (regardless of what others say that you cannot). The jump makes all the difference in the world. I use .01 or .015" jump to the lands with subsonic 308.

BTW, I have had bullets keyhole with Clays subsonic where Trailboss did not keyhole. CCI BR2 primers.
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Artful
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Post by Artful »

johndoe3 wrote: I have never had a 220 gr SMK keyhole at 100 yards with 1 in 10 twist in my 308 (regardless of what others say that you cannot). The jump makes all the difference in the world. I use .01 or .015" jump to the lands with subsonic 308.

BTW, I have had bullets keyhole with Clays subsonic where Trailboss did not keyhole. CCI BR2 primers.
Isn't reloading fun - each rifle a law unto it's own - I have a friend with a redhawk just like mine but his gives 150 to 200 fps fast chrono's with same ammo - no matter what ammo we try - and he won't swap what kind of friend is he? :lol:
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JohnInNH
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308 Subsonic Good Results!

Post by JohnInNH »

I finally got good results with the 308

22" 5R Mike Rock GAP M700 1:11.25 twist

Winchester brass, Winchester primer

Trail Boss powder

150 gr Hornady RN Flat base and 170 Hornady RN Flat Base

I went up to 9.4 gr in the 150 bullet

998
1003
1033
1018
1007

Average= 1011 FPS, ES = 34, SD= 13

I will settle in at 9.5 gr and call it quits.

I shoots very well. All sounded consistent.
My goal was 1000 fps - 1050 fps.


The 170 gr bullet

10.5 gr Trail Boss

1056
1020
1000
986
1009
Average 1014, ES= 69, SD=26

I am going to go up to 10.7 and call it quits there.

The exterior ballistics for the 170 and 150 are very close at up to 150 yards.

Sighted in at 100 yards scope height at 1.9"... bullet path is about 3.5" high at 40-70 yards... 1.5" high at 90 yards... then 1.9" low at 110 yards. 4" low at 120 yards..

The 170 gr bullet has 325 ft lbs at 100 yards, and 299 ft lbs at 150 yards.
The 150 gr bullet has 286 ft lbs at 100 yards, and 263 ft lbs at 150 yards.

The 150 is a much softer point and will expand easily. I think the 170 is made for more rugged conditions.

For most of my applications the 150 will do. The 170 for larger critters or where I need more penetration or to knock over steel..

Rodents and raccoon size game the 150 Hornady would be a good mix.

The sound of the bullet hitting the hemlock stump was by far louder than the "report" M700 GAP AAC short Cyclone
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Rikky Lee
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Post by Rikky Lee »

I found Extreme Spread to be the killer in my load development at ranges beyond 50 - 60 yards. Going from a one hole 50 yard group to a 6 inch vertical group at 100 was heartbreaking at times.

Keep up with the experimenting!
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Post by JohnInNH »

One of my favorite quotations

"A man's got to know his limitations" ~~Dirty Harry, 1973 "Magnum Force"


I feel the limitations in a 308 case and having a ES of 35 is not that bad. I can live with that. I figure 100-120 yards is about the most I will use those loads for... When I build my 300 whisper I will work on better loads.
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Post by Fulmen »

First off, I'd go for a faster powder, there really isn't any reason for choosing anything but the fastest powders in a case this big. I use VihtaVuori N310 (the fastest available I think) in my 30-06 and it works quite well. I haven't tried it beyond 50meter though...
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Post by dieselten »

thanks for all the detailed load data (even though it is for a 308 8))

I loaded up some 30-06 with 150 grain bullets and 11 grains of Trail Boss to check the windage zero on the newly mounted iron sights. They were subsonic and fired nice and clean. I will try it at the range next weekend.
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