Finnish Army tests on the M39

[Vince24]

Hi everyone

I got this article in English regarding test conducted by the Finnish Army on the M39.

I found this hugely interesting - it's not everyone who can do tests over more than 15,000 rounds!
Have tried to attach below, let me know if you can't read it, can send you again via messages.

barrel15.gif (284.98 KiB) Viewed 1414 times

barrel14.gif (290.2 KiB) Viewed 1414 times

I note in particular:

- the bullet speed they have on the 200gr D166: only around 700 m/s. To get that low with 2208, I think you need to be under 40gr, which is really like below the minimum according to ADU data. Yet according to many, this is the speed at which the D166 shines, accuracy-wise.

- the fact that it takes 15,000 rounds for the grouping to start getting less good! As the owner of an M39, it bodes well to me!!!

- the tests with different bullet diameters.

Cheers,
Vince

[bladeracer]

Has some interesting information. Don't suppose you have the Figure 3 of the sectioned throat?

[bigrich]

i had a old sporterised turk mauser in 8x57 years ago . the barrel was shortened to 20" and recrowned. and at 50 yards it would shoot under a inch and around two inches to inch and a half at 100 with a feild instruments rear peep sight . the amazing thing was there was no rifling for the first two inches from the throat !

i shoulda kept that one .....

[straightshooter]

Has some interesting information. Don't suppose you have the Figure 3 of the sectioned throat?

You should try looking at the bottom of the second page where fig. 3 resides.

[bladeracer]

Has some interesting information. Don't suppose you have the Figure 3 of the sectioned throat?

You should try looking at the bottom of the second page where fig. 3 resides.

Bugger, I was expecting to see the throat actually sectioned

[Vince24]

I was wondering if there are people reloading the M39 with D166 around here and what the experience is. Got some D166 with the rifle, have to try the authentic Finnish experience!

I will also try some 308 projectiles (ELD 178) out of curiosity!

I understand from the above study that as long as the bore is too wornout, the smaller diameter projectiles will shoot fine - they had to go above 10,000 rounds for the larger diameter projectiles to really make a difference in accuracy.

[bladeracer]

I was wondering if there are people reloading the M39 with D166 around here and what the experience is. Got some D166 with the rifle, have to try the authentic Finnish experience!

I will also try some 308 projectiles (ELD 178) out of curiosity!

I understand from the above study that as long as the bore is not too wornout, the smaller diameter projectiles will shoot fine - they had to go above 10,000 rounds for the larger diameter projectiles to really make a difference in accuracy.

Under-size bullets will likely work better if they have plenty of bearing surface, a blunt point and a flat-base for example. Be interested in your results with the ELDM/X though. I have long wanted to try .308" bullets in the .303 but I keep forgetting. You will probably need to neck-size the brass in a .308" die though to be able to grip the smaller bullet well enough to feed through the action.

[straightshooter]

I was wondering if there are people reloading the M39 with D166 around here and what the experience is. Got some D166 with the rifle, have to try the authentic Finnish experience!

I will also try some 308 projectiles (ELD 178) out of curiosity!

I understand from the above study that as long as the bore is too wornout, the smaller diameter projectiles will shoot fine - they had to go above 10,000 rounds for the larger diameter projectiles to really make a difference in accuracy.

I suspect that you didn't read the graph correctly.

[JohnV]

First thing I notice is that projectile is a rebated boat tail so that means it's been hand made possibly on a single set of swaging dies not commercially made in hydraulic ejecting transfer presses which can make a smooth transition boat tail but hand swaging can't . This should give better accuracy than bulk made bullets would and would make the round seem more intrinsically accurate than most people would be able to achieve with standard components .
Such large amounts of rounds fired would bring barrel wear into the equation fairly badly and it's obvious no private shooter would be paying the ammo bill . It's historically interesting and somewhat informative but it's also has a component of advertising . No mention of cleaning procedures which concerns me and could explain the 3 to 5 inch groups which is horrible in my book and under such shooting conditions not really possible to test the true accuracy potential of the rifle and ammo . I agree with the gas flow erosion we have all seen it . It's a shame they never tested pure moly coated bullets after that .
It's interesting but I'm not sure what it really proves to just hammer away firing so many rounds other than the barrel went ok for about 10 000 rounds which is not remarkable and don't use undersized bullets which we can't buy anyway . Oh and no custom bullet maker puts a cannula in a target style bullet it upsets the air flow over the bullet and lowers the BC .

[straightshooter]

JohnV
Your speculation regarding the projectiles is way off.
They are simply Lapua FMJ bullets that have been in use since the 30's and are still available in some standard calibers.
Many countries did similar research testing and similar tests are referenced in the British textbook of small arms although nowhere near as detailed.
As a side note the British tests found considerable muzzle wear which was attributed to improper cleaning.

[JohnV]

JohnV
Your speculation regarding the projectiles is way off.
They are simply Lapua FMJ bullets that have been in use since the 30's and are still available in some standard calibers.
Many countries did similar research testing and similar tests are referenced in the British textbook of small arms although nowhere near as detailed.
As a side note the British tests found considerable muzzle wear which was attributed to improper cleaning.

You could be right but that bullet shown looks hand swaged to me . The very small edge to the rebate indicates a fine edge to the base punch which makes the punches fail in commercial processes but Lapua may have done it that way to look hand swaged . I have also seen muzzle wear problems from the incorrect use of pull throughs on Military weapons .
The research is very interesting but it's not that relevant to how most people use rifles now .

[No1_49er]

I'm sure that if you do an image search or Lapua projectiles the D166 in particular, you will find any number that look like your "hand swaged" version. Lapua produce them in vast quantities.

[JohnV]

I'm sure that if you do an image search or Lapua projectiles the D166 in particular, you will find any number that look like your "hand swaged" version. Lapua produce them in vast quantities.

I will take his word for it .