Subsonic 7.62x54R


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FM90Master
September 30, 2013, 10:47 PM
Is there any website, or store where one can buy 7.62x54R subsonic rounds for the Mosin Nagant?

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greenlion
September 30, 2013, 11:59 PM
There were, at one time, some import training rounds with very light bullets. I don't think subsonic ammo with a normal heavy jacketed bullet would be very accurate. Bullets require some speed for the rifling to stabilize them. You can always reload and download the rounds with H4895 or Trailboss.

Tolkachi Robotnik
October 1, 2013, 12:49 AM
Subsonic is pretty slow. I have never seen any data for reloading even cast bullets that gave speeds under 1200 fps for rifles of this general size. That would be nine or ten grains of Unique and a small bullet for .32 pistols, .313 or maybe sized smaller. It would perhaps not work in all rifles due to throat dimension differences, most common trouble cracking brass near neck constriction or end of shoulder. Don't try this without doing a lot of reading about it, and maybe attention to the exact bore diameter of your specimen. The thirteen grain loads of Unique are not subsonic, and they ruined brass at a high rate in my M44.

The cases are pretty high volume for pipsqueak loads. If you were going to try it with jacketed bullets I would suggest 123 grain or smaller ones made for the 7.69X39. I doubt if this sort of thing would be available commercially due to a lack of demand.

KansasSasquatch
October 1, 2013, 02:17 AM
The low recoil stuff varies in velocity but I believe the 46gr hollow core goes about 3000fps. I've seen some 123gr advertised that went about 2400fps.

To get a proper subsonic x54R cartridge I would suspect using a heavy 200gr+ cast bullet with Trail Boss would be the best option. Using a heavy bullet and lighter charge is normally the way to get to subsonic levels. But too light of a charge and you're risking a squib.

Cosmoline
October 1, 2013, 07:20 PM
TB and lubed heavy hardcast is the way to go. I've worked some up but didn't chrono them. I was thinking about doing some black powder rounds along these lines but velocities would likely go supersonic.

Ike Arumba
October 1, 2013, 09:17 PM
You could try a chamber adapter to shoot .32ACP through it.

Cosmoline
October 2, 2013, 01:30 PM
My bet is the extra barrel length will put enough oomph behind a .32 ACP to get it supersonic, and any reduction of powder risks a barrel obstruction. That safety concern is why I stick with the lead bullets for these kinds of experiments.

Ike Arumba
October 2, 2013, 04:15 PM
Ballistics By The Inch tested four loads in .32ACP. The Cor-Bon 60gr. JHP reached supersonic speeds, but the other three stayed firmly subsonic out to an 18" barrel, at which point the speeds were dropping with increasing barrel length.
http://ballisticsbytheinch.com/32auto.html

Cosmoline
October 2, 2013, 05:18 PM
Good point, but one thing concerns me--the FMJ's are showing velocity drop by 15-16". A Mosin's 28" barrel could see them decrease in speed too much. What about the loss of jackets to burrs out there towards the end of the bore? Either way I'd stick to lead.

Ike Arumba
October 3, 2013, 03:34 AM
Fair enough. I haven't tried it, and brought it up just on a lark. (But it seems that someone has taken it seriously enough to market the adapters.)

KansasSasquatch
October 3, 2013, 04:07 AM
Another problem with chamber adapters is that they effectively turn a bolt action repeater into a bolt action single shot.

If I were going to try it I would most likely use Trail Boss. Hodgdon's website has data for .308 Win and .30-06 using Trail Boss and Nosler 150gr BT. For both cartridges the minimum charge shows about 1100fps and the max charge is over 1400fps. 7.62x54R data is generally right between .308 and .30-06 data. Going off of that theory the minimum charge for the x54R with 150gr bullet and Trail Boss, the minimum charge would be about 11.5gr and the max would be about 16.5gr. However, I would most likely start with the 10.0gr min charge from the .308 data. I'd be very cautious in making sure both the bullet core and jacket exist the barrel. Having never used Trail Boss personally I could be wrong but I think using Dacron filler between the powder and bullet would be a good idea. And I wouldn't attempt it without a chronograph.

Another option would be to step up to 180gr bullets and use Hodgdon's method of filling the case to the base of the bullet (DO NOT COMPRESS TRAIL BOSS). It wouldn't likely be sub sonic but you can work your way backwards from there, and use Dacron filler, until you reach sub sonic velocity without sticking a bullet/jacket in the bore.

You'll have to make your own decisions, I'm simply telling you what I would do if I desired a subsonic x54R load. I don't know if a Mosin barrel will even stabilize 150gr+ bullets at sub sonic velocities. Calling Hodgdon may be a good idea. They won't give you any definite information if they haven't tried producing such loads, but they might be able to tell you if its a solid theory.

carbine85
October 3, 2013, 09:59 AM
I haven't reloaded anything subsonic but I have decreased the load in surplus ammo and reloaded lesser charges in my reloads. While it was nice to shoot I couldn't achieve any good accuracy with the rounds.

Cosmoline
October 3, 2013, 01:39 PM
But it seems that someone has taken it seriously enough to market the adapters

That's an excellent point. I'm probably just being paranoid about it. I've just heard that jackets going too slowly can shed.

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