Finn M39 reloads help

[MilsurpMI]

I have recently ordered a M39, It's my first venture into the Mosin family and I am told I won't be disappointed with the rifle. I have never loaded for the 7.62 (Typically a U.S. & Mauser guy) Is there anyone out there who is willing to save me some time on a good reload for this rifle?
I am reading about a D166 200gn load that was pretty specific to the M39, any pointers, good duplicates, what velocity should I be looking for?
I read an earlier post mentioning 40.0gn of IMR 4895 pushing a 200gn bullet. Has anyone tried this out?
Also, I read that the Finns used a 7.62X53 but were also able to shoot the 7.62X54 captured Russian. Should any considerations be made for this during reloading?
Any tips on souping up my rifle if I feel it isn't shooting like it should?
Any thoughts or suggestions would be greatly appreciated.

Information

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[Parashooter]

CIP publishes specs for both 7.62x53R and 7.62x54R, attributing the former to Finland (FI) and the latter to Soviet Union (SU). The only significant difference is maximum projectile diameter: 7.85mm (.309") for the x53 and 7.92mm (.312") for X54. Maximum case length for both is closer to 53.5mm than to 53 or 54mm. See the specs at http://www.cip-bobp.org/homologation...-en-page28.pdf and http://www.cip-bobp.org/homologation...-x-54-r-en.pdf

M39 barrel dimensions are normally something of a compromise between loose Russian standards and the tighter barrels of the M28/30. Jacketed bullets .310" to .311" usually work well.

It's often unproductive to try shortcutting the load development process by soliciting specific recipes from internet forum participants. You have to find what works in your rifle with your specific lot of bullets and powder. With decent bullets that fit the grooves, a good M39 is hard to beat -

[Bruce_in_Oz]

Because most MN variants have a BORE diameter of close-enough to .300", they will also run happily with .308" bullets.

One trick I have seen, not actually owning one myself, is to load "surplus" 150gn., ball (FMJ), ex-30-06 type, and play with loads.

Yes, a .311"-.312" bullet may be ideal.

The Finns themselves seem keen on their "match" variant, the 7.62 x 53R, which is essentially a fancy load using .308" match bullets in the standard case (just use the appropriate expander ball / plug when case sizing). The Finn, Moisin Nagant-actioned, MATCH rifles for this are built with .308" groove barrels, but, plenty of people seem to mix and match. A good, clean M39 could be an eye-opener in this case.

The trusty old Lee Enfield .303 squirted .311" FB FMJ bullets out of barrels that regularly, and within spec., ran out to .319" / .320" groove diameter and could deliver some pretty impressive groups at 600 yards.

[Parashooter]

Given some of the assertions in the previous post, I suspect Bruce and others might find this old article interesting -

Attachment 75092Attachment 75093

[Bruce_in_Oz]

I am keen on bullets that "fit" the groove size, even to the point of using "oversized" bullets on occasion; like "soft" .311 soft-points in a particular .30-06 that shot exceptionally well with them.

"Bore-riders" are not a new thing, as indicated by the longevity of the .303.

They may also not be an ideal thing, but you get that at times.

Furthermore, gas-bleed is MUCH greater with boat-tails of the solid based (like most "sporting" projectiles), than with "open-based", FLAT based FMJ types. Hit an "open-based" bullet up the rear end with 40,000 plus PSI and it is unlikely to stay at the original diameter for very long. Has anybody got the article, I think it was in the British "Guns Review", that detailed experiments with ULTRA short rifle barrels and reaming out the bore itself?

My recollection is that the recovered bullets showed measurable expansion at their tail-end when fired in short, slightly-oversized, smooth-bored barrels. The rather rapid burn-rate of traditional Cordite may have been a contributing factor.

This feature is a direct carry over from the earlier, muzzle-loaded Minie ball of P-53 Enfield, etc., fame, i.e., a "bore-rider" with an expandable "skirt" that sealed the rear and also helped "scrape" out the residue from the previous shot. Earlier editions of this bullet design had a small "plug" inserted into the hollow base of the lead bullet. this was designed to be driven into the slightly-tapered recess on ignition and force the "skirt" out into the grooves. It didn't take long for someone to discover that this plug was not necessary as gas pressure, even from a black-powder load, was sufficient to do the job.

Going to the .577-450 Martini Henry bullet introduced a few new "funnies".

Henry's original bullet design tapered from .450" at the base to .439 near the nose. Experiments carried out by a certain Dr. Mann, from about 1890 to 1910, strongly indicated that the best bullet for black powder was a bore-rider, with a rear band increased to groove size.

Kynoch production up until the 1960s, kept this idea and their bullet measured .452 at the base and .446 at the nose. with a thin paper patch, this came out to .460" and .455 respectively.

Using more traditional "cartridge" paper, these days fashionably referred to as "artists" paper, the diameter at the base comes out to .470", conveniently assisting the fit of the bullet into the case. Like the bullet, the case NECK is nominally tapered, from .516" at the rear, just forward of the "shoulder", to .507" at the mouth. Thus, it seems that the patched bullet was dropped into a "partially" formed case and sat on the powder load topped with the beeswax "wad" before the case was sized down onto the bullet.

Oddly enough, this concept carried over to the .303 round. This, of course, was originally loaded with black powder, but this was not dribbled into a fully-formed case. The case was basically "straight" sided and looked a lot like a .444 Marlin. Into this, a "pellet" of compressed black powder was inserted, a "glazeboard" wad followed and THEN the final taper and neck were ALMOST finish formed. The bullet was inserted on top of the wad and the whole thing then sized and the bullet crimped in with annular or stab crimps that lined up (hopefully), with the cannelure.

The Cordite loads were done in much the same way, with the little bundle of propellant inserted BEFORE final case forming. Ever tried to get the Cordite out intact?

The other trick with the Martini bullet was in the Henry's rifling, which is a marvel to behold: It is "nominally" seven-grooved, but there are actually fourteen "lands" of two different widths and ALL "lands and grooves" are radiussed. The "theoretical" .464 inch "groove" diameter does not appear as such, much the same as in the seven-"grooved" Metford and five-grooved Enfield rifling on the later Lee based rifles. Nominal "bore" size is .449", a lot closer to .450" than .38 (special) is to .357"

Anyway, we have veered a bit away from loading for the Finn M-39

[Parashooter]

. . . Ever tried to get the Cordite out intact?

Yes; it's easy. (Getting it back in is the hard part!)

[Bruce_in_Oz]

Getting it back in is the hard part!

Good point. Hence the way the ammo was manufactured.

Especially interesting to get back in "intact", is the wad, which, as clearly shown, is about the right diameter to sit nicely a few mil. back from the shoulder.

See pic.

Has anyone stripped down any of the WW1 / WW2, US-made stuff loaded with granular powder, to look for a wad?

[Parashooter]

WRA 1943 - spherical powder, no wad.

[MilsurpMI]

Thank you for the info Parashooter! You have given me a great base to start with and work from there.
looking forward to unboxing the rifle. It will be at my FFL tomorrow

---------- Post added at 12:24 PM ---------- Previous post was at 12:22 PM ----------

Thank you all for the great info!

[MJ1]

I recall a short film clip from a lecture in the mid '60 at school that showed the cordite injected into the case before neck shaping. Now that function would have to be so accurate that no trim to case finish followed.

Thank you for the post !