Home Forums Hunting & Shooting Custom Rifles & Wildcats 7.62x39 Improved Project

Some time ago I bought 2 Howa mini barreled actions; a 6.5 Grendel and a 7.62x39. Both have 20” lightweight barrels. Howa mini’s are smooth actions with nice hunting trigger. My only complaint is the bottom metal. ‘Nuff said.

A consummate tinkerer, I decided to try 7.62x39 improved version. There was no good reason for this. The hope was to get 30/30-ish performance out of the rifle/cartridge combo.

CH4D had 28 degree dies on the shelf. Whoda thunk? Mike Bellm had a reamer and did the rechamber job to match my CH4D dies. “Conversion” is as simple as firing factory ammo in the rifle. Nothing else. Capacity before/after fireforming is roughly 3 grains of AA1680 powder or 11%.

I built a Mannlicher stock for the barreled action(s)s. Mannlicher stocks can be frail so I reinforced it with pillar and full length bedding. There are 3 recoil lugs supporting the stock. An old Nikon fixed 4X scope is mounted in Tally base-rings. The unloaded rifle weighs exactly 6lbs.
When I fireformed a box of WW boxer primed 123 ammo average velocity was about 2250 fps. Today I loaded the same cases with 30 grains of AA1680 powder over Hornady 130 (.308) spire point bullets. This is about a 95% load with a COAL= 2.230”. Chronographed velocities = 2594. 2602, 2598fps. Accuracy for 3 shots at 50 yards was ½” cloverleafs. Encouraging results for a first try.

I believe 2500 FPS is possible with 150 grain bullets and a COAL = 2.390”. This is the limit of the Howa magazine. Generic 123 grain 7.62 bullets might approach 2800 FPS.

All disclaimers apply . These results exceed SAMMI specs for the cartridge because it was designed for the AK platform. However, these PSI levels are well within the capability of the Howa bolt action, which is chambered for other cartridges in the 50-55,000 PSI range and a similar bolt face. At any rate, in my rifle, extractions was easy, primers are tight, bases are not expanded. I see no excess pressure signs.

The little Howa carbine wonderfully accurate & potent. The “conversion portion” of the project cost me about $200. Besides learning something, I got quite a bit of extra performance.

Next steps, test 150 grain bullets, try .224 saboted [ Accellorator] ammo, and finish the rifle.

Sounds pretty danged neat to me and it might be a lot of fun too!

Hopefully you can post a few pictures.

Please post pics. If you have brass issues consider necking up Grendel brass

berets and michy, can you tell me how to post pix on the campfire?

https://www.24hourcampfire.com/ubbthreads/ubbthreads.php/galleries/15052487#Post15052487

Guys, I created an image gallery at the above link. But I have no idea how to make them appear in the original post, like I see in other posts. I can post them IMGUR, but that is temporary. I find the navigation extremely frustrating on this site and I have worked in IT a long time. How doe san average mortal make this work so you can see images for this project?

Dang, that is slick.

This is a cool project. Keep us posted on the 150's and saboted bullets. What kind of wood did you use for your stock?

Very cool! That is a slick little rifle!

That is a sweet rifle!

I really like my Mini Grendel. Great trigger and just a super handy little rifle.


Did you carve the stock or dupe a pattern?

I had some somebody semi inlet a walnut blank which was alleged to have lot of flaws. I thought I could work around them so I took a chance. It is a really gorgeous piece, with lots of color.

The "flaws" turned out to be irrelevant because over 1-1/2 lbs of wood was removed to get a real Mannlicher Schoenauer-style shape. She has two coats of Permelyn sealer. The sealer will be cut back to the surface so a traditional a hand hand rubbed oil finish can be applied. The keeps the wood sealed and allows an oil finish. Also, the barrel needs refinishing anyway so I will rust blue the barreled action.

The real proof will be in the performance. I should be able to swap back an forth between the 7.62x39AI and the Grendel to see which one I like the best. Who knows maybe I will have to carve a second Mannlicher for the Grendel.

That looks like it is going to be a beautiful little rifle. Please keep us up to date on your progress. Bet it will shoot great, everyone is going to want one.

Sweet! Kind of puts you in 300 Hamr territory in a smaller package, can't beat that!

That’s a cool little rifle and I like what your doing with it - keep us updated!!

PennDog

I did something very similar with one of my Howa mini’s in 7.62x39. I made a 30 caliber bushing for a 6.5 Grendel reamer and reamed the 7.62 chamber with it to just clean up to the neck. I bought a clearance 6.5 Grendel sizer reamer and it was easy enough to make a resize die for the .311 Grendel version. I had the same thought of getting the 125gr bullets into the 2600+ range to increase performance on medium game in expansion window and increased range. My results were similar to yours.

Cool project! Thanks for sharing, and looking forward to more about it as you go along.

Go 224 Grendel.

Hint.........

Did you bob the mag on that? It makes them a lot handier than having the long mag hanging down.

Howa Mini 6.5 G with bobbed mag



The 6.5 Grendel getting the job done Put the plastic stock on for on the bike.

Funny you asked. I bobbed the magazine just today. It still holds 4 rounds. Much cleaner look. Wish the bottom metal was flush, but it is what it is.

Have you seen Oregunsmithing bottom metal?

They make a nice looking unit.


http://www.oregunsmithingllc.com/

Mike Bellm is great on chambers and throats, IME. I like it all. Nice package. I’ve always had a true .308/7.62x39AI in the back of my mind, as a ‘new age’ 30-30 clone, but never pursued it. ...only real difference being .308 bullet selection positives. ....on the flip side, I think the Grendel is far more suited to the small bolt guns for hunting performance, vs in an AR.

You’re making me want to grab one of those minis and have it shipped to you for a stock. LOL