H4895 in 7.62 x 39 with Lee C312-155

[milrifle]

In reading past threads on 7.62 x 39 it seems 26.5 to 27.5 gr of 4895 is an acceptable load with a 150-160 gr cast bullet. However. Hodgdon's web site lists 27gr as a starting load and 28gr as a max for a 150gr J-word. I loaded up some at 26gr which was a compressed load. I have to wonder if 28 would have even fit? At any rate, there were no pressure signs, but it grouped like my 19 gr RL-7 loads. Too big. I backed off to 25 gr of H4895 and they got better. I backed off to 24gr and they got even better. This is opposite of the way I would normally work up a load, but I think I would like to back off even more until they either the groups open back up or it fails to cycle the action. But I am concerned about being so much lower than starting loads. Even at 24 grains, the case was what I would consider full. It may not have been compressed, but it dang near was. Anyone have an idea if I am OK to keep backing off or am I looking for trouble?

[WILCO]

This book:

[milrifle]

That book doesn't show 4895 in the 7.62 x 39.

[Yodogsandman]

See post #4 in the following link...

http://www.castbulletassoc.org/forum...766&forum_id=8

Also see the Hogdon 60% rule for H4895...

http://www.hodgdon.com/PDF/H4895%20R...le%20Loads.pdf

Here's another great article in post #1...

http://castboolits.gunloads.com/show...light=7.62x54R

Want more? See page 3, paragraph starting with "similar"...

http://home.comcast.net/~gavinsw/gun...itaryrifle.pdf

My personal favorites are 21.0gr Reloader 7 or 25.5gr IMR4895. YMMV

[GhostHawk]

I commonly shoot 20 gr of IMR 4895 but I do mine behind a Lee .312 185 gr Gas check bullet that with gas check and lube weighs 190.

They are I am guessing about 1/3 slower than factory loads. (No Chrony)

But they shoot to point of impact, the groups have consistently kept shrinking to where I am getting golf ball sized or smaller in a 10 round bunch out of my SKS.

Heresy I know, no one told me I couldn't shoot heavy bullets out of that barrel. LOL I probably wouldn't have listened anyway.

Accident? Pure Luck? Dunno, don't care, it works.

Next summer, testing will switch to experimenting with Red Dot and maybe lighter boolits, but I'll be keeping most of my ammo loaded with 4895 and heavy boolits.

With H4895 you can in theory drop to 60% of load for reduced loads. So IMO, sure try 17, and work back up.

[WineMan]

Most of my bullets shoot to point of impact too...

Dave

[WILCO]

That book doesn't show 4895 in the 7.62 x 39.

Then try this book:

[WILCO]

The answers are out there. With a little research, you'll have them.

[jethunter]

If you can afford it, Quickload software is great for these kind of questions.

[milrifle]

Wilco,

You seem to imply I did no research. I will admit I did not check the Lee book, but they seldom if ever list the bullets from their own molds, so I forget I even have it. I did check the Lyman book. I also read many past threads, including all but one that Yodogsandman listed, before I ever posted the thread. My question was not "What is a good load for the 312-155 in 7.62 x 39?" My question was more along the lines of "Why is the published minimum load already a compressed load and is it safe to load it lighter than that?" Ghosthawk is doing so with no problems, so I think I will give it a try unless someone else knows of a potential problem.

I do appreciate the responses. Thanks.

[Yodogsandman]

Two points to consider.

GhostHawk is using a boolit that's 30gr heavier.

Do you need the pressure to operate your gas system?

Also, I read through the article by C. E. Harris again and noticed that he HT'd his boolits, I'm HT'ing mine right now to try it out. Can't hurt.

[milrifle]

I haven't set up my chrony, so I'm not sure what velocities are, but I started out with RL-7 and worked up until the action cycled, which was at 17 gr. I loaded up several at 17 and while the grouping wasn't too bad, they didn't cycle every time. I moved up to 18 gr and the groups got worse and I still had 1 in 25 rounds that did not cycle. I moved up to 19 and got reliable cycling, but the groups were totally unacceptable. So I figured I would try 4895 thinking I could get some pressure to operate, at lower velocities. I started out at 26 gr which was the low end of what I had read others were using with this bullet, but the group sucked. I then began lowering the charge in an effort to lower the velocity and also, because I wasn't comfortable with the compressed charge that 26gr and even 25gr was giving. 24 gr of H4895 comes right to the base of the bullet, but the groups are still bigger than the 17gr of RL-7. I wish I had chrono'd them, but I think I would like to get down into the velocity range that the 17 gr of RL-7 gave me, but with a powder that will have enough pressure to cycle the action. I suspect that somewhere in the 22 gr range of H4895 might be a good load, but it was so much below what others were doing and also below Hodgdon's minimum load for jacketed, I wanted to ask someone more knowledgeable than I first.

[arjacobson]

I have told many guys about this load in 7.62x39.. Different powder but same bullet. 22grains of 4198... Excellent load...

[WILCO]

Wilco,

My question was more along the lines of "Why is the published minimum load already a compressed load and is it safe to load it lighter than that?"

Milrifle,

It's all about learning. I mentioned those reloading books because they answer the questions you have. Sometimes you have to dig into the research to understand the endeavor at hand. The LEE book has a chapter on powder reduction and "Never" reduce powders. Best wishes and stay safe.

[truckjohn]

Reloader 7 is the classic 7.62x39 jacketed powder.... The stuff works very nicely usually...

I know this is a dumb question and all... but... Have you slugged the barrel and fitted a bullet to your actual barrel dimensions?

Checked the gas system for lead - to make sure it's not shaving lead off the bullets and making them go wobbly...

Anyway... when working up cast loads- some loads tend to get worse, then tighten back up... BUT... If you are shooting loads too hot for your bullet - they get way worse as you up the powder... At that point - your barrel is probably all leaded up....

The solution here is to go with harder bullets and a slower powder....

So.. You went with 4895 - which is WAY slower... Likely slow enough to shoot huge fireballs and give you a strong "Crack" when shooting...

Have you tried a harder bullet sized slightly larger?

Thanks

[leadman]

I shoot the Lee 312-160-TL in my Norinco SKS with a .313" bore. My boolits weigh 170gr with the Hi-Tek coating and gas check. Don't remember the exact amount of H4895 but it just under max listed. I have a 4X mil-Dot scope on it and it will shoot 2" at 100 yards consistently with some groups smaller. Velocity is over 2,300 fps. Cases are expanded less than Win. factory ammo and no flat primers, primer pockets stay tight after about 3 or 4 loads so far.

I have slugged probably a dozen SKS rifles and all of them were over the supposed standard of .310". Most are around .313". The faster RL7 might be bumping up your boolits where the slower H4895 isn't. I recommend at least 18 BHN for an SKS.

[Buckshot]

7.62x39 28.0 surp 4895, Lee C312-155-2R, 2018 fps, fired at 50 yards, iron sights.



It has a .300" x .308" bore

.............Buckshot

[chrispy]

What is the brand/build of your rifle Buckshot? I like it!

I am about to embark on building a 308 barrelled 7.62x39 on a ruger 77. A bit of fun.

Chrispy

[GREENCOUNTYPETE]

the lee reloading manual has a section on cast boolit reduced loads in 30-30 308 and 30-06 so this dosn't help you exactly but what is does tell you is that since it lists loads down to 15gr with 30-30 and 170gr bullet that lower is not an issue with H4895 it doesn't do strange things when reduced , I have gone on the low end 15gr and 19gr in 30-30 and all that starts happening is your cases start turning black as it is not expaning the brass so well or burning completely , but if you work backwards from where you are at you should be just fine when the neck shows black you hit the bottom end

it can be possition sensitive but if you tip your muzzle up till you find where you want and then if it is less than 2/3 of the case maybe research dacron filler but I don't think you will need that in 7.62x39 it is a small case

[GhostHawk]

^

7.62x39 is quite close in case volume, average bullet weights, and ballistics. Not a match, but as Greencountrypete says, points on a curve. One that points you in a safe general direction.

Trial and error works too, sometimes, but when it doesn't it can hurt.