Subsonic load testing in a M96 swedish mauser

[Andy]

Ok so I have the bug and have been shooting this as much as possible. Today I got up there and did the first 20 round test with the same powder charge. This was the 3.0gr bullseye charge. Keep in mind bullets are seated a little deeper now than any previous test and I charged all cases with the lee dipper without weighing after the first 5 came in right on the nose.

Here are the results of 15 rds fired at the same target after 2 fouling shots. (shot over a dry patched barrel, not fully cleaned from last session)
- 14 of the 15 shots were inside a 1" group, had one bullet land .5" lower than that group and I don't feel like it was due to a bad shot (checked each shot with spotting scope after firing), possibly a low charge due to bad fill of the lee dipper.
Low: 610 fps
High: 667 fps
Avg: 644 fps
SD: 17 fps

Group impacted dead on vertically with the irons set to the 400m setting.

I should have mentioned this before but I am not dead on with windage as I had previously thought. I realized this a few sessions ago but did not update what I have written. Looking back at the targets, I have been consistently hitting a little to the right on all of them, this 15 shot group confirmed that. Center mass of the group was 3/4" to the right of the point of aim so I think I need to adjust my sights. I'll wait until I have a load picked to do so though.

With my 3 remaining shots I tried it out at 50 yards on a clay bird on the sand bank, 400m was too low, 600m was too high, but when I put the sights to 500m I satisfyingly destroyed it on my last shot. Not scientific, but since I could see the rounds impact due to the light recoil I think this will test out ok when I move out to 50 yards later in the test.

Thanks for the idea on the dowel, wouldn't be hard to make up one of those on the wood lathe.

[Andy]

Prepared 20 more rounds today with 3.5 grains but have not had a chance to fire them. In order to reduce potential sources of inconsistencies I did the following to these cases before loading them:

- Trimmed (only the lightest amount came off, but it was more on some than others due to some cases getting 5.5 and others getting 2.0 since the last trimming), chamfered and deburred again.
- Wet tumbled cases in stainless pin media as they had not had a full cleaning since first firing.

- I also decided to not use the lee dippers again (did only for the last 3.0gr test) and will use my ohaus measure for all future 20 rd tests, including this 3.5gr batch I just did.

Ordered an M die as well, last batch I loaded the lead shaving was minor but very annoying and I plan to load for this caliber a lot so might as well own something repeatable. Really enjoying my m dies for the other calibers I have.

[leadman]

You can get just the "spud" without the die body direct from Lyman. IIRC they are $7. If you have the correct die body. this is the way to go.

[Andy]

Leadman, thanks for the info. I do appreciate the concept and realize there is considerable savings to go that route but I like to leave my dies set up for one thing and not have to change them once it is dialed in so I have been slowly getting an M die per cartridge I have and have been very happy with the results so far. It just makes it so nice to place/seat a bullet without any setup or fuss that it is worth the extra $20 to me. I want to keep this rifle forever so I figure having an M die on hand for the caliber is a good investment.

[Black Beard]

I’ve played with subsonic loads in 310 cadet . It is a tiny case (1cc of water capacity behind a 120 grain .322 bullet).

The following are from memory:
1.5 grains of trail boss consistently stuck the bullet a few inches from the end of the barrel. When the bullet did got stuck in the barrel then the residual pressure ejected the case out of the action when I opened it.
2 grains gave big variations in velocity and something like 500fps. Very quiet.
2.5 grains gave about 750fps and was getting consistent.
3 grains was consistent 12fps SD.
3.5 grains was about 950fps and was consistent 12fps SD.

4 grains was what I normally shoot- about 1000fps and really good accuracy. It fills the case with trail boss.

You can get 30 calibre air gun pellets that might work better at very low charges. They would work out at about 15 cents each. I expect that you could propel one of these with a magnum or shotgun primer.

310 cadet rifles are expensive antiques but 32 H&R or 32 S&W should be very similar if you want to get serious about reducing noise.

You might find this interesting:
http://guns.connect.fi/gow/arcane1.html

Or buy an air rifle for the squirrels and use pellets heavy enought to keep velocity below 900fps.

Lower velocity rounds can change windage as well as elevation. My 7.5mm is way out with 1500fps 180 grain lead loads.

BB

[cuvy]

If this helps, one data point for you:

7 grains of Trail boss with a 140 grain powder coated cast lead projectile (commercially produced - hawkesbury river blackhawk) gives around 995 fps out of a standard Husqvarna M38. Haven't played with varying charges or seating depths, but this gave at least 1" groups at 50m.

[Andy]

Did some more testing over the last few days:

3.5 grain test: 15 shot group at 25 yds measured 1", keep getting 1" groups right on the nose, maybe .9 or 1.1" if you split hairs but I don't want people to read 1" all the time and think I'm just eyeballing, they are right at 1" groups with a tape measure.

L: 731
H: 771
A: 751
SD: 12.2

Next day I did a 4.0 gr batch but I have the M die in now and messed up my neck tension as I was not sizing deep enough once I incorporated the M die bump out step. I knew this group would be useless for test data so I used it to get the windage adjustment on, I'm now dead on for windage at 25 yds. If I remember right the math I looked up in an m96 manual online worked out to 1/64" drift adjustment meant a 1MOA impact shift at 25 yds. My actual results were that it took more like 1/32" but I wasn't measuring precisely.

**After shooting the 20 shots of 4.0gr I felt like it was too loud for what I'm going for so decided to go back to 3.0 and confirm a zero for that to use that load as my solution for my primary goal of quietest load that holds a 1" group out to 25 yards. Main reason for picking 3.0gr is that it is the quietest load tested so far that holds 1" accuracy to 25 yards.

Loaded up another 3.0gr batch toward that end, sizing a little deeper now so no neck tension issues. This group was right at 1" at 25 yds again and dead on the bullseye for group center mass with sights at 400m. This time I also shot a second 4 shot group on paper at 50 yds, that group was 2.5" and the center mass was 1"low and 1"right at 50 yards with sights at 500m. Recorded the following data:

L: 620
H: 665
A:643
SD: 12

Life is a good bit nicer with the M die setup now, no more lead shaving or smeared lube.

I have had so much fun with this, and have been anticipating using it on game greatly so I decided to take these 20 cases and leave them as my 3.0 hunting cases and loaded up another batch of them right when I got back from the range.

It may be a while until I continue the test to find the best subsonic load out to 75 yards, possibly a next winter project. When I do I'll probably dip into my other brass supply and set a separate group for that so I can keep this brass set aside for this 3.0gr load. In the meantime I'm very glad to have a functional quiet round I can shoot right now out to 25 yds, just in time for summer pests. My next likely test will be to test this 3.0gr load more thoroughly at 10/15/50 yards and also give it a try at 75 and see where it hits there.

Thanks for all the thoughts and input, this has been very fun and I hope the data is useful to the next guy going down this path with a swede.

[OS OK]

Hi Andy…I too am starting to work loads that will be on the light side although not the same application as yours in a Yugo M48. So far I have only been 'searching' the threads for all the info I can find as I don't want to repeat all the work done somewhere else just for the sake of doing so.

One thing I have read…don't know whether or not it is true…but…you are the perfect guy to find out…"Is these extremely low powder loads 'position sensitive' in the case? If so, that would make them 'vertically string out'…I think."
Would you try to find out by doing your test with intentionally positioning the powder up next to the shoulder by tipping the rifle down and then carefully placing it on the bags and firing? The other side is to tip the rifle muzzle to the sky and getting all the powder to rest at the base of the cartridge and then carefully setting it on the bags and firing.
Compare at least 5 or so rounds to each extreme and publish your assessment of the results?

Thanks, very interesting this thread…will be following closely!…OS OK

[Andy]

OS OK: Glad you asked about the position sensitivity. I should have mentioned before that periodically throughout the tests I loaded some rounds by tapping the cartridge on the table, primer down, twice then loading in the rifle upright to test this. Other rounds I pointed downward (no tapping) then loaded in the horizontal rifle. I watched every shot through a spotting scope at 25 yards to see if there was a change and did not detect any consistent difference. This aspect of the test wasn't done scientifically but I did it somewhat regularly and paid attention to it throughout. My subjective results were in keeping with what I have read regarding bullseye being a "not position sensitive powder" so I think it is a non-issue in this particular case.

It is also possible that the results of the change are only evident past 25 yards, which I did not test for.

[Andy]

Well I finally got to kill something with it, I went out with the rifle for a short half hour hunt and had good luck to get a chipmunk and a red squirrel.

Chipmunk was shot on the ground at about 10 yards, flopped back like he was on a hinge and never moved, in the chest and out the back spine area with no visible expansion of the bullet based on wound size. Heard the bullet careen off through the trees at an odd angle afterward.

Red squirrel was shot almost absolutely vertically in a tree, had to dodge the body as he fell. Shot him through a 2" dry dead stub branch on a pine tree, hit him in the gut unfortunately and he lived/crawled for about 20 seconds and got under a fallen log. Took another shot at his head at 10' and he stopped moving. Turns out I missed the 10' shot and he just happened to die then. Recovered body showed one massive (1" or more) entry wound into the stomach and no exit wound, so guessing he died from wood/bullet shrapnel from a nearly spent bullet when I shot him from below in the tree.

I wasn't too happy that the gut shot wasn't lights out with a 140gr bullet but I know red squirrels are tough and it was a slow round going through a hard pine branch so i guess I won't draw too much from it at this point. Makes me worry it might not be near enough for a relatively clean kill on a coyote though.

Might test pure lead bullets to try for more expansion next. I'll keep the thread updated as I go along. Found 10 more mixed brass in the range bucket so I have a bit more to play with now while keeping a hunting reserve.

[Catch]

I wonder if you could use a 25 caliber bullet at 60 grains and paper patch it from .258 up to .264? One way to try a much lighter bullet?

[GONRA]

Based on GONRA's 6.5x50.5 Jap experience,
try making a paper tube that slldes into the neck of the 6.5mm cartridge case,
dump in (you'll have to tweak this) 18.5 grains IMR 4895
and use a Lyman 266469 cast bullet.

[RU shooter]

Glad to see your experiment is still going strong and working well for you . For some real fun with them take it out to 100 or even 200 yds and see what happens . Yes I know now what you really started this for but is sure is fun shooting subs at steel gongs at longer range . My favorite sub load with the 30-06 would hit a 12" plate at 200 consistently . Neat hearing that bang and second later clang .