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Nice straight ogive, from the case mouth to the curve. Lots of barrel bearing surface.
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04-10-2020 06:06 PM
# ADS
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The deep, rearwards cannelure is an interesting feature. Not unlike Mk7 .3.3 bullet. Of course, that cannelure was not intended for case-mouth crimping, but to carry a waterproofing sealant and the Mk 7 bullet was "stab-crimped" in place anyway.
It may also have that big cannelure in that location for a different reason. If it is "rolled" into the jacket to sufficient depth, the jacket will form a "constriction" inside the bullet. Could this be as a form of "extra" core retention, intended to reduce core separation after initial impact. Standard 7.62 NATO projectiles start to upset and tumble when they strike anything much harder than air and often rupture at the "knurled', rolled cannelure if upset enough.
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Seems the closest we've come to identifying these is the Finnish 7.62x53R
Just found THIS!
"Because the Finnish Army considered the S-1 bullet too inaccurate for rifles and inappropriate for machine-gun use, a new boat-tailed service bullet with a crimping groove was developed in 1932-1934. The resulting design, known as D-166, was introduced in 1936. This bullet had gilding metal jacket just like the D-46 and D-47 but weighed 13 grams (200 grains), was 33.8mm long and, for a certain reason, had somewhat increased diameter (7.87mm). Because of the bullet weight the powder charge was dropped to 2.85-2.95 grams and burning rate was slightly decreased as well. Although the D-166 was more material consuming bullet to manufacture than the S-1 it became more economical cartridge to make as copper and lead were much less valuable than powder at that time. Therefore production of the S-1 bullets was halted in 1939 and the D-166 became the standard cartridge of the Finnish Army. The main manufacturer was VPT but also Sako and temporarily loading shops established in 1940 (Patruunalataamo 41, 42, 43 and 51) loaded D-166 cartridges. VPT started production in 1936 which halted in mid 1940 during the Interim Peace. A year later, just before the Continuation War, the D-166 went back production which lasted until early 1944. This was because a more economical 10.8 gram (167 grain) spitzer bullet with conical base cavity, the S-283, was introduced in late 1943. Externally this new bullet looked like a D-166 cut just in front of the boat tail for which reason it was fitted with a knurled ring to distinguish it from the heavier D-166. The S-283 was replaced by gilding-metal-clad steel jacketed version known as S-284 in June 1944. The charge VPT used for both bullets was 3.15 grams of tubular nitrocellulose powder. At some point in late 1944 or early 1945 the D-166 was reintroduced once again."
Last edited by doc540; 04-19-2020 at 10:14 AM.
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The Finn TKIV sniper is built around the 7.62 x 53R round. This is essentially a very refined version of the venerable Russian round. The trick is that the barrels were essentially "western" 7.62mm bore and groove; hence the .308" (ish) bullets, including, apparently some SMK or Lapua match-bullet type. The trick is that about the only compromise in this conversion was to use chamber and throat dimensions that would allow the use of "standard ball" ammo in "emergency". Such a concept od "exclusive" ammo can also be found with the Russian SVD and its special ammo; the 7N1, which is topped with a 152 grain FMJBT projectile and which is made on dedicated production lines and one plant: Factory 188, also known as Novosibirsk Low Voltage Equipment Plant .
The last word in Mosin Nagant variants. With many of the receivers being culled from "liberated" Russian rifles, the guts of many of these rifle can be over a hundred years old. Makes an L42A1 look positively sprightly.
Apparently, the TKIV series have been phased out in favour of a nice, green Sako of more "Mauser-sh" heritage.
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Sorry, That should be: "7N14" cartridge as the current Russian "special" round.
There is a "7N1" but it was introduced in the sixties with the introduction of the SVD and superseded by the 7N14 in 1999.
BOTH were successful attempts to squeeze a significant "accuracy" improvement out of the trusty old 7.62 x 54R.
I'm not a total "ammo guy", but, back in the 1950's, when Olympic shooting was a bit more "butch" than 10metre indoor air-rifle events, the Soviets got quite a bit of attention with impressive scores delivered by "racing" versions of the Mosin Nagant, firing the original cartridge, probably from carefully selected batches.
Last edited by Bruce_in_Oz; 05-30-2020 at 12:53 AM.
Reason: But Wait! There's MORE!
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