Zastava 7.62x39 Restoration

There seems to be a few fans of these M85 Zastavas so I thought Id share this little rebuild.

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Technically this one is a Interarms MarkX but its just a Zastava in a prettier stock and apparently nicer machining.

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Unfortunately this one had a crack in the walnut from the rear action screw right down the wrist top and bottom.

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The crack was easy enough to repair by spreading it slightly with a wooden wedge just in front of the action screw and running some very thin epoxy resin into it before clamping it up and lightly sanding it while the epoxy was still wet. Its a good trick to hide the crack with walnut dust of the same colour. This works best if you scrape all the old stock finish back around the crack and remove as much of the action oil blackend wood that tends to leach in if it has been cracked for some time.

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The heal had had a repair at some stage too so I tidied that one up while I was in a wood working mood.. (thats about never)

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I bedded the action and epoxied in some steel pillars in to give some added strength to the repairs.

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It came up pretty good. The entire stock was then scrubbed down with thinners to remove most of the factory oiled finish. A few good coats of Tru-oil and it was all sorted.

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The barrel was well corroded in the grooves but it still had pronounced rifling so I was hopeful it might still shoot well enough to use as a bush basher. I picked up some lapua brass and some Hornady 123gr SSTs to give it a crack. I tried some loaded to full mag length and some crimped into the canlure.

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After failing to hit the target board at 100m which was 3A4 pages high I moved closer to 50m.
I landed 5 shots on paper scattered about 30cm apart!
Plan B.. Re-barrel with a new MAB .308 bore barrel.

wow thats a piss poor pattern to be sure...lovely job on the stock.....might just have to do mine one day...maybe over winter,all your talk of pillars has got me thinking I should put some in mine.

You won't be disappointed they are excellent actions but that barrel is definitely gone.

Got a 308 off Brian,short barrel suppressed, lovely trigger and great to shoot, Brian has one in .223, another hunter has on in 7mm mag, all very accurate rifles nothing wrong with Zastava.

@nor-west be in quick and grab the M8 4X in buy sell NOW and put it on the 08....trust me the rifle will feel completely diferent and come up to eye soooo much quicker.

@Micky Duck has a lovely old Burris 2-8 courtesy of Brian, just fits the mauser action, good thick crosshairs low down for the bush, got the 257 Weatherby and 280 AI for that long range stuff.

Is it possible to button rifle or acid etch the rust out as an interim measure?

Before I got started on the new 7.62x39 barrel I had a .22 grendel itch I had to scratch..
I had a very short trueflite 1-8" twist .223Rem take off barrel that I wanted to test the .22 Grendel reamer on so I got to work on that one first.
Once the rooted barrel was off I gave the action a quick true up and lapped the lugs.
The finished grendel barrel came out at a short 13" but as a test rig thats all I needed.
I made up a few cartridges from some 6mm PPC brass (.220 Russian parent case) as all my 6.5 Grendel brass is currently loaded at the moment.

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Like the 6.5 grendel that can get its max velocity from only 14.5" of barrel the .22 Grendel gave an impressive max load speed of 2800fps at the muzzle with 77gr TMKs and BM8208.

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I havent spent any time developing a load but even at the
max charge I was comfortable with it grouped very well.

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More on this cartridge later but the barrel was stripped off again and shelved while I made a start on the 7.62x39 barrel blank.

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Quote:

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Originally Posted by Russian 22.

Is it possible to button rifle or acid etch the rust out as an interim measure?

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Nah it was propper fuct.. I gave it a good scrub and bore lap but the grooves have receded from the original groove dimension of .311/.310" to .323" :wtfsmilie:
so it may have shot 8mm projectiles ok..

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So the MAB barrel blank I selected is a 25" long 4140 CM 1-10" twist light Sako contour in a .308" bore diameter. The profile was a fraction lighter than the Zastava barrel but I am planning to my this bushy as light weight as I can while still keeping with the classic look.
It was to be cut to 15.5" long which puts the over barrel suppressor just off the stock to keep it as compact as possible.

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I have gone away from the std .310" 7.62x39 bore for a couple of reasons, one being the availability of a wide range of projectiles for the .308 over the .310 and secondly as a bush basher I like to have a few subsonic loads handy for goats which is why I stayed with the fast 1-10" twist over a more suitable 1-14" for 125gr bullets.
I will mostly use 125gr TMKs and Nosler 125gr balistic tips but would like to try some of Hornadys new 190gr SubX in it too.

For these reasons I have also chosen to use the 7.62x39 Lapua spec reamer which has no freebore to speak of but has a gradual taper from the case mouth down to .300" at the top of the rifling. This reamer is listed as being suitable for the heavier 150gr X39 loadings and also for the American made .308" bores. This tapering of the lands is also a fail safe insurance that it wont over pressure if you run std 310" bullets down the .308" bore.

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The first thing I noticed was how sloppy this reamer cut the body of the cartridge dimensions. I guess it was a copy of the military CIP chamber which has very generous tolerances for multiple reasons. Automatic arms in this cartridge get hot.. with heat tolerances tighten, throw a handful of dirt, carbon buildup, crappy steel case lacquer coated ammo and those extra few thou are justified.

However, I want to build something that shoots a little better than your average milsurp rattley AK47 shooting steel cased Cobloc corrosive ammo into 6" groups at 100m so this added chamber slop made me nervous.

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After scrubbing out all the inhibitor grease and polishing the bore a bit I blued it and got set up to load some test rounds.

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I was just now wondering about the neck area of your chamber...by using the .308 button and partial length resizing we were going down 3/4 of way on neck resized with a sort of bump/2nd shoulder ,brass life wasnt too bad but it makes it work a lot more than if we were using fatter button and projectiles.
you will enjoy the 125 nosler ballistic tips BUT you will probably need to seat then till lip of case JUST STARTS to get into oglive area...I did to fit mag of norinco bisley anyway.

Yes that is basically where I ended up.

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After loading a few 125gr TMKs and finding a load with 2207 over the chrono I found the case formed to the chamber nicely and all slop at the rear went away.
I tried hard to make the Redding full length sizing die work with a .307" expander ball even trying to short size the case left the case body over re-sized and sloppy in the chamber.
Regardless I tried the loose fitting new brass rounds on paper at 100m and it shot about an inch and a half.

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I finally gave in and shot down to Workshop Innovation and picked up a Redding 7.62x39 neck sizing die and changed out the expander ball.
With the fire formed brass passed though this die down about 70% of the neck leaving 30% still blown out to the chamber dimension it help with tighter chamber alignment and didnt re-size the case body at all.
Now they fit snug and I put a second group at 100m on paper. This time only 3 shots. The heat and mirage was real bad and I was shooting through a 6 power scope so I was pretty happy with the results!

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Fantastic results yet again

lilgun could well be your new best friend.....got a mate to run quickload figures for me and it works rather well.

Got about 500gms of CFE BLK if you want to give that a go too. It got me up to 2600fps in a Howa Mini.

Quote:

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Originally Posted by Micky Duck

lilgun could well be your new best friend.....got a mate to run quickload figures for me and it works rather well.

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Im listening... what sort of speed are you getting from lilgun? The 2207 is maxing out at 2150 in the 15.5" tube.
I went with the TMKs as they were designed specifically for .300BLK. Sierra knew they had to shoot well with a jump from AR15 mag lengths to the long BLK throat designed to shoot long 240gr bullets. They seem to jump fine in this chamber too. Like the 125gr Nosler they have to be seated down to the ogive to fit the Zastava internal mag.

Yes 19 to 22 grains of Lilgun are ok loads for this projectile.
Estimated velocity 2100 - 2300 fps
Be careful when creeping up past 21 grains


Cartridge : 7.62 x 39 (.308) Elvis
Bullet : .308, 125, Nosler BalTip 30125
Cartridge O.A.L. L6: 2.200 inch or 55.88 mm
Barrel Length : 20.0 inch or 508.0 mm
Powder : Hodgdon Lil'Gun

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-06.0 68 18.80 2117 1244 30993 3817 100.0 1.267
-04.0 70 19.20 2151 1284 32642 3861 100.0 1.241
-02.0 71 19.60 2184 1324 34369 3906 100.0 1.216
+00.0 73 20.00 2218 1365 36180 3949 100.0 1.192
+02.0 74 20.40 2250 1405 38076 3993 100.0 1.167
+04.0 76 20.80 2282 1446 40062 4035 100.0 1.142
+06.0 77 21.20 2314 1487 42142 4077 100.0 1.118
+08.0 79 21.60 2346 1528 44321 4118 100.0 1.095 ! Near Maximum !
+10.0 80 22.00 2377 1569 46602 4159 100.0 1.073 ! Near Maximum !

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 73 20.00 2282 1446 43243 3799 100.0 1.117 ! Near Maximum !



I dont own a chronygraph

Quote:

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Originally Posted by Pommy

Got about 500gms of CFE BLK if you want to give that a go too. It got me up to 2600fps in a Howa Mini.

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What barrel length is your Howa? Hodgdons load data put a 24" barrel with a max charge at 2550fps

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I went with 2207 after trying 2206H and BM8208 which only gave 1950fps so an even faster powder in this short barrel may claw back a bit more velocity. Correct me if Im wrong but isnt CFE Black a slower burn speed than those Ive tried? Its not a powder Ive ever used.

Its a bit of a trade off with case capacity in this load because the bullets are seated very deep meaning I cant get close to a max charge in any of the bulkier slower powders which means I need smaller charges of hotter powder.

Thanks for that @Micky Duck
That data looks very similar to the speeds and pressure Im getting with 2207 in a shorter barrel so Im not sure I could safely gain a lot more with it.
Lilgun makes me nervous after toying with it in my .22 TCM, 10.5gr was a great load with no pressure signs then10.8gr would blow the primer and ass out of the case!
It spikes quickly with very small increments.
My current max listed load of 24gr of 2207 behind the 125gr TMK shows no sign of pressure but I have tried pushing it past that. 2205 might be a more stable faster burn to try in this shorter barrel. I don't want to kill brass but it would be nice to get every bit of energy I can get from it.
H335 was another listed powder that shows good speed but I normally avoid dirty temp unstable ball powders.

as said I dont do the chronicgraph thing..... I didnt push loads till pressure signs,just picked load and shot stuff...in case of bush range reds...very dead.

Nah CFE BLK is quicker than H335/BM8208/AR2206H. Very close to AA1680 which on Powder equivalents - ADI World Class Powders and Ammunition is roughly around AR2205/AR2207. Not to be confused with CFE223.

I think the Howa was chopped to 15" but I might be remembering that number from my CZ527 which had a 18.5" tube before it became a Grendel. Lots of room in the mags to load them longer and no pressure signs past 30gr.

Lyman manual I have lists H335 as their most accurate powder so I gave it a go in the CZ. Velocity lagged behind 2207 by about 100fps at max loads and the fireball was huge. Too slow. I'd steer clear of anything slower than AR2219 (which works great with 150's btw) for that reason.

Quote:

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Originally Posted by Pommy

Nah CFE BLK is quicker than H335/BM8208/AR2206H. Very close to AA1680 which on Powder equivalents - ADI World Class Powders and Ammunition is roughly around AR2205/AR2207. Not to be confused with CFE223.

I think the Howa was chopped to 15" but I might be remembering that number from my CZ527 which had a 18.5" tube before it became a Grendel. Lots of room in the mags to load them longer and no pressure signs past 30gr.

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What sort of fill does 30gr of CFE Black give you?
Is it a fine extrusion powder or ball?
If you check out my pics of the loaded 125gr TMK v/s the one sitting beside the cartridge and you can see it is seated well below the case shoulder taking up case volume. I think if I could climb over max loads in my deep seated rounds with that CFE black it would compress and give pressure much sooner than yours loaded out long.

24gr of 2207 kisses the seated projectile but doesnt compress it, there is still a slight rattle.

Ball powder. Can't recall if my loads were compressed. A quick Google suggests the vmd for CFE BLK is .0659 vs .075 for 2207. So BLK is more dense.

24gr AR2207 * 0.075 = 1.8cc's. 1.8cc's * 0.0659 = 27.3gr CFE BLK for equivalent volume.

Quote:

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Originally Posted by Pommy

Ball powder. Can't recall if my loads were compressed. A quick Google suggests the vmd for CFE BLK is .0659 vs .075 for 2207. So BLK is more dense.

24gr AR2207 * 0.075 = 1.8cc's. 1.8cc's * 0.0659 = 27.3gr CFE BLK for equivalent volume.

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Thanks for that, good info

Flick me a message if you want to give it a go. Pretty confident you could gain a fair bit of speed.

Ok... so Im an idiot.. in a moment of distraction I have used the wrong powder data!

I knew something wasnt right, many years ago I had a 16" AK47 that I loaded for that had no problems getting over 2400fps with 2207. I kept asking myself, what has changed? 1/2 an inch less barrel length surely wasnt the issue.

Nope, I had used Hodgdons load data which I had saved as a shortcut on my phone knowing that ADI AR2207 is the same powder re-labeled for Hodgdon as H4198.
However at a glance I selected IMR 4198 which has the same numbers but different burn rates. The listed max charge for the IMR was 24gr which seamed light when I was testing.
After checking ADI's website I realised what Id done.

So with a new found max charge of 26.5gr I went back to the chrono and settled on a charge of 25.5gr @2350fps.
26gr only gained 10fps so the 2207 is getting a full burn at about that in my short barrel.

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Can anyone explain to me why IMR shares the sane numbers as many of the ADI/Hodgdon powders but have very different load data?

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I had a Howa Mini in 7.62x39 for a while too. I ran mine with 125's (both BT's and Speers, no noticeable difference) and was getting average MV's of right on 2500 fps with 30 Gns of CFE BLK with no pressure signs. According to the boys at the 300BLK forum CFE BLK performs "best" with a little bit of compression and while I haven't used a lot of it I'd say its probly a valid observation.

@Dama dama
Shes all finished.. although it could do with the barrel being dumped in a hot blue tank which I will have done at some stage to give it a darker more durable blue than my make shift cold blue job.
The M8 compact Leupold arrived today which I gave a good clean and touched up the anodizing where needed. Great little combo. A nice short and light bush basher for sure with enough grunt to take down anything in range.

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Glad scope turned up alright. Perfect on that rifle. While thing looks great, nice work on the wood work.

now that is just downright sexy.....3x loopy I take it???

Cheers guys, yeah it came up nice. @Micky Duck its a 2.5x20, should be great in the thick stuff.