Anybody loading 7.62x39 +P for Bolt Actions?

[MSR_Gal]

Is there any data out there for full diameter bolt actions in 7.62x39? Loaded to 55K instead of 40K.

Obvious you wouldn’t want to use such data in AK’s, SKS’s, AR’s or mini bolt guns like CZ 527.

Due to pre-’98 7x57 Mausers, 8x57 1888 Commission rifles, and 6.5x55 Norwegian Krags, all of thee cartridges have developed 2 tier loading data.

Has anyone done this with the 7.62x39 in Savage 10 FCM Scouts and similar actions capable of handling 55K even with .308 case head size?

 

[2506]

For powders suitable for that round they are already compressed loads.

 

[gunsandgunsmithing]

Is there any data out there for full diameter bolt actions in 7.62x39? Loaded to 55K instead of 40K.

Obvious you wouldn’t want to use such data in AK’s, SKS’s, AR’s or mini bolt guns like CZ 527.

Due to pre-’98 7x57 Mausers, 8x57 1888 Commission rifles, and 6.5x55 Norwegian Krags, all of thee cartridges have developed 2 tier loading data.

Has anyone done this with the 7.62x39 in Savage 10 FCM Scouts and similar actions capable of handling 55K even with .308 case head size?

For bullets from 110-125 grain range, 4198, rl7, 1680, n120, 5744, norma 200.

I've campaigned a
30 Major(grendel) since 2007 with pretty good success. It's slightly larger that the x39 and has proven to be a very good cartridge.

Strictly in terms of accuracy, the x39, with good brass,bullets barrels and equipment, it should shoot very well too.

 

[MSR_Gal]

For bullets from 110-125 grain range, 4198, rl7, 1680, n120, 5744, norma 200.

I've campaigned a
30 Major(grendel) since 2007 with pretty good success. It's slightly larger that the x39 and has proven to be a very good cartridge.

Strictly in terms of accuracy, the x39, with good brass,bullets barrels and equipment, it should shoot very well too.

I've got a barrel on order with McGowan. .311 groove diameter, 1:16" twist, and what McGowan calls their "7.62x39 Match" chamber - basically the 7.62x39 Lapua chamber developed by Lapua for Valmet. I plan to use bullets no heavier than 125 grains, so 1:16" should be more than adequate.

 

[MSR_Gal]

For powders suitable for that round they are already compressed loads.

The powders currently considered to be the correct burning speed have been selected on the criterion that a full case generated 40k or less pressure. If we look at it as a new cartridge, we need to determine which somewhat faster powders will give us 50-55k pressure with a full case.

 

[gunsandgunsmithing]

I've got a barrel on order with McGowan. .311 groove diameter, 1:16" twist, and what McGowan calls their "7.62x39 Match" chamber - basically the 7.62x39 Lapua chamber developed by Lapua for Valmet. I plan to use bullets no heavier than 125 grains, so 1:16" should be more than adequate.

JMHO, but I'd cancel that order and get a standard .300/.308 barrel, if you plan to handload for it. There are many good 30 cal light bullets but you are extremely limited with .311 bullets.

Is there a particular reason for using the unmodified x39 case?

 

[Zero333]

I agree with gunsandgunsmithing.

Get a .308" barrel if you're handloading.

A 0.308" barrel will shoot 0.311" bullets with out generating excess pressure.
Ruger mini-30 was originally made with 0.308" barrels and nobody had any issues shooting surplus .310"-.311" ammo.

And go with a 13" twist because the 0.308" 125gr Nosler ballistic tip needs a 13" twist to fully stabilize at 2,000 fps at sea level, according to Berger's twist calculator.

 

[MSR_Gal]

go with a 13" twist because the 0.308" 125gr Nosler ballistic tip needs a 13" twist to fully stabilize at 2,000 fps at sea level, according to Berger's twist calculator.

The online calculators are based on the Miller Twist Rule formula. For lead or lead core/copper jacket bullets this has been shown to give better results than the old Greenhill formula. But for plastic tip bullets, Miller yeilds extremely conservative results. As a result Courtney derived a modified Miller formula to account for pastic tip bullets, Google "A Stability Formula for Plastic-Tipped Bullets" for a 2 part paper describing the new formula and the experimental validation done. 125gr plastic tipped bullets will be fine in 1:16" twist.

 

[MSR_Gal]

JMHO, but I'd cancel that order and get a standard .300/.308 barrel, if you plan to handload for it. There are many good 30 cal light bullets but you are extremely limited with .311 bullets.

Is there a particular reason for using the unmodified x39 case?

This barrel is a bit of an experiment. I want to see how good Russian steel case will shoot with bullet diameter grooves, optimized twist and a better throat to begin the bullet's journey. The primary cause of this ammo's poor performance is poor static and dynamic bullet balance. This causes radial group dispersion. The faster the bullet is spun, the greater the radial dispersion of the group. So going from 1:9.45" to 1:16" should yeild a noticeable decrease in group size. No bullet is perfectly balanced, so even the finest match bullets should benefit from keeping the stability factor between 1.4 and 2.0. Since their balance is so much better, the improvement will be less, But it should still be measurable.

 

[GSPV]

I'd add LT30 to that list of powders. LT-32 might work in your application, depending on how much velocity you need.

I campaigned one of Mike's 30 Majors for a long time. Would still be, if I was shooting IBS score. Best rifle that I've ever owned. Hated to part with it.

It was a 1:18 twist Krieger. I shot 115 and 118 grain flat base bullets in it at 2850.

 

[joshb]

This barrel is a bit of an experiment. I want to see how good Russian steel case will shoot with bullet diameter grooves, optimized twist and a better throat to begin the bullet's journey. The primary cause of this ammo's poor performance is poor static and dynamic bullet balance. This causes radial group dispersion. The faster the bullet is spun, the greater the radial dispersion of the group. So going from 1:9.45" to 1:16" should yeild a noticeable decrease in group size. No bullet is perfectly balanced, so even the finest match bullets should benefit from keeping the stability factor between 1.4 and 2.0. Since their balance is so much better, the improvement will be less, But it should still be measurable.

I'm no expert but I got some expert advice from Randy Robinette on my 30br build. I tried some Sierra 125s in my 17 twist and made some nice keyholes. Randy did some figuring and posted his results. I just bought a Bartlien 13 twist, thanks to his advice. You should look at his post. It's down in the 30br section. I think the cartridges are similar enough for it to apply to what you're doing. Keep us posted on your results if you go with the 16.

 

[GSPV]

It’s all about the length of the bullet...

Attached is the very last group that I shot with mine before parting with it. 118 grain Hillbilly 7-3/4 ogive bullets with a relatively mild load of Tubal 2000. That’s 5 shots at 100 yards with no tuning of any kind. That’s a 1:18 twist. Length of the bullet...

 

[MSR_Gal]

I'm no expert but I got some expert advice from Randy Robinette on my 30br build. I tried some Sierra 125s in my 17 twist and made some nice keyholes. Randy did some figuring and posted his results. I just bought a Bartlien 13 twist, thanks to his advice. You should look at his post. It's down in the 30br section. I think the cartridges are similar enough for it to apply to what you're doing. Keep us posted on your results if you go with the 16.

If you are talking about 125 gr SMK, then I see what you mean. I'm having to take an educated guess as to its length without tip. According to Miller formula 1:16" will handle no more than 0.96" long and that would be on the ragged edge. It looks like your bullet would need around 1:13.7" to get to the ragged edge of stability (stability factor ~1.4), so I have to agree with your 1:13" choice. The bullets I plan to use are ,310/.311 a maximum of 0.900" long.

 

[joshb]

Ok. I have a couple other 30br's I shoot the custom bullets in. I'm building a fun gun to shoot the cheapies. Good luck with your project. I need a little help with this stuff. Still learning. Josh

 

[MSR_Gal]

Bullet length appears twice in the Miller formula. In one place it is a squared term. In the other, it is not squared. In the Miller formula modified for tipped bullets, the unsquared length term is still the full bullet length. But for the bullet length less tip is used in the squared term.

So a Hornady .310 123gr tipped SST in a 1:16" twist would show an unacceptable 1.27 stability in the original formula but shows a safe 1.51 stability in the formula corrected for the effect of the plastic tip.

 

[odette]

I have an unknown custom 14" barrel for a TC Contender. I have no clue what the twist is, but it is a .311 barrel in 7.62x39. This is something my grandpa picked up 30 yrs ago for silhouette shooting. I found some loads that he made, IMI brass, 1680 powder, Federal primer, and a custom rebated boattail 145 gn JSP with a long taper that looks like the Sierra 155 gn Palma bullet. I have fired 15 of these rds and they are very accurate. 1 hole at 50yds from a Ransom Rest. I have 123 gn either Rem or Win that don't come close. Are there any good 140 gn to 150 gn bullets in .311 dia. I think the 123 gn bullets are meant to be sprayed out of rifles and not meant for accuracy. My purpose for the load is to be able to knock down steel rams at 200 meters, so want something heavier than 123 gn

 

[DocBII]

Is there any data out there for full diameter bolt actions in 7.62x39? Loaded to 55K instead of 40K.

Obvious you wouldn’t want to use such data in AK’s, SKS’s, AR’s or mini bolt guns like CZ 527.

Due to pre-’98 7x57 Mausers, 8x57 1888 Commission rifles, and 6.5x55 Norwegian Krags, all of thee cartridges have developed 2 tier loading data.

Has anyone done this with the 7.62x39 in Savage 10 FCM Scouts and similar actions capable of handling 55K even with .308 case head size?

Check the Vihtavouri reloading data. They used to have a number of loads. I like the 150 SMKs, but load them for the SKS.

HTH,
DocBII

 

[D-4297]

You made mention of using the Russian steel cases , so I'm going to take it for granted these are non-fired cases that the bullets have been pulled from , or you are familiar with Berdan primers . If not , I strongly recommend not trying to convert these cases to a Boxer primer . It can get very ugly , very fast . Over-lap in the distance of the two Berdan holes in the case can cause blow-back if a Boxer primer isn't precisely installed . Nam Vet with 2 AK's , 1 SKS , and 3 M-N's and very familiar with going down that primer rabbit-hole . Just thought to offer a caution to this experiment .

 

[Rdlningcltchdmpr]

For bullets from 110-125 grain range, 4198, rl7, 1680, n120, 5744, norma 200.

I've campaigned a
30 Major(grendel) since 2007 with pretty good success. It's slightly larger that the x39 and has proven to be a very good cartridge.

Strictly in terms of accuracy, the x39, with good brass,bullets barrels and equipment, it should shoot very well too.

You mean r7 not r17 ?

 

[Rdlningcltchdmpr]

I've got a barrel on order with McGowan. .311 groove diameter, 1:16" twist, and what McGowan calls their "7.62x39 Match" chamber - basically the 7.62x39 Lapua chamber developed by Lapua for Valmet. I plan to use bullets no heavier than 125 grains, so 1:16" should be more than adequate.

I've got a match reamer,762×39/308 bore. Much better because of all the match bullet's from 108-125 weight. My howa mini/Krieger shoots in the low two's- mid one's. I also shoot 30AR- 17 twist here's a picture of 125mk-1.120" long. They group very well in 17 twist