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

I have thought about a 9x39 on my mini-Mauser 223. Sounds like fun using the improved case and a 180 gr Barnes X or a hard cast WFN. Looks like a great gun for fun and compact, easy to swing full stock. Reminiscent of the old Steyr M/S. Be Well, Rustyzipper.

Madmooner, I had not. Very cool!. I bought an aluminum replacement from DIP, but it is a the same pattern as the original. Had I know about this version I would have bought it. Maybe next time.

By all means do it. Looks great and works perfectly. Only way I'd stick with the DMs was if I was hopping in and out of vehicles. They make it for the .222 family rounds now too. I was going for the DIP unit before I saw the Oregunsmithing one.

They were out of sock when I got to the site. Put myself on the notification list. I agree with Madmooner and Pappy348. Bought one and keeping the DM. The latter with both a long and bobbed magazine. That way I have three options for the two barreled actions. Can't wait to try out the hinged floor plate. Maybe Legacy will take the hint and boot the bottom-plastic solution. Besiding being plastic, it breaks.

There is another option by Jefferson Outdoors.

Single stack hinged floorplate. Opens COAL a bit.

https://www.jeffersonoutdoor.com/shop/howa-mini-flush-bottom-metal

Pretty much given up on Legacy taking the hint on anything. It galls me that the boys from Oz still get SS, including Minis while we have to slum carbon steel and that crappy paint they push. Reminds me of the folks at Ruger who apparntly think we all want 16" .300 magnums.

Cool stuff!
But I bought the 76239 for cheap plinking and my boys hunting rifle. (Cz527)

I bought one as well for my grandson to use, but it was a Mini. Kills deer just fine. Now that I have the Oregunsmithing unit fir my Grendel, he has two magazines.

Yes, sir. Based on your prompt I googled and found Jefferson Outdoors. Put myself on the waiting list Will improve the profile of the Mannlicher.

I bought the complete bottom metal from Jefferson Outdoors. It was a perfect swap out for their aluminum mag well. It really cleaned up the Mannlicher profile. Very nice people to work with.

I would love to see a picture of a finished round!

Here is the link to the imagages

https://www.24hourcampfire.com/ubbt...ies/15149116/7-62x39ai-ammo#Post15149116

posted a link of ammo for you.

That's pretty cool looking buddy!

The 30PPC with a 115 bullet is about 3000-3100FPS and very accurate. Same thing as a 7.62x39 ackley

Berger's, right? I am sure you are correct. I haven't gone that way yet. Because this is a little carbine, I was thinking more toward 150-160 grain bullets at moderate velocities like 2500 ish for medium game. While an accurate and handy hunting rig, this is no BR rifle. I don't think i "invented" anything unique. I was astonished about the similarities to the 30 Grendel, 30 ARX, and now the 30 PPC. It makes sense. 220 Russian, begat the 22 PPC, 7.62x39, then the 6.5 Grendel, back to the 30 Grendel, and the 30 PPC. All of these must be about the the same, except for minor dimensional difference and of course, bore diameter. Good call. Think I will google load data for the 30 PPC.

I believe the Grendel has a little more powder capacity. Mike Stinnet has the World Record small 5 shot 100 yd group at .0077" He calls it a 30PPC, but it was based on the 6.5 Grendel brass. He used 114 grain bullets at 2980fps with a very stiff load of H4198 in a 17 twist Kreiger.

Interesting, Butch. I bought a bunch of PK (American-Lapua PK brand) 7.62x39 brass. Necked it down to 6.5 Grendel. The PK 3 grains less capacity than Hornady-Grendel.

Anyway, I wanted to re-convert the Grendel back to 30. Found the extractor would not engage the case over the rim of the case. So, I necked a few over 30 cal, then back to 30 to get a false shoulder. Same problem ocurred. I could not get the Grendel cases back into use as 7.62x39 cases. This suggests my Grendel chamber must have a shorter shoulder dim than my 7.62x39 AI. Meanwhile the 7.62x39 is a pretty tight fit with factory ammo. So, I do not think the AI conversion was messed up. Is still fires factor ammo without any hitch.

What I do know is the re-conversion should have worked, but it did not. Ego, my Grendel may not be larger than my 7.62x39.

2980 is smokin' What about brass life at these levels. Also, my rifle has a 1:9.45 twist.

Dan

I don’t think I’d try to run the Howa Mini anywhere close to the pressure of a hot benchrest load. The bolt lugs are nowhere near as robust as any full size action much less a benchrest action. Just food for thought.

A Ladder test with 150 grain bullets in the 7.62x39 28 degree Ackley.

Today I set up a test using the following recipe: 150 grain .312 Speer bullet with H4198 powder. COAL = 2.325. Federal Match Large Rifle primer. This case holds 39.5 grains of fine ball powder to the case-mouth. Brass Geco factory brass, fire formed to improved chamber. (Once fired brass)

The rifle: Howa Mini. 20” light weight barrel. 7.62x39 Improved 28 degree.

The purpose was to see if the cartridge could duplicate 30/30 performance. I used 30 ARX load data as a reference. My cartridge has slightly more capacity than the 30 Grendel, 30 ARX, so I started with the lowest load and worked up. The test measured 3 rounds fired at each level.

Results

Grains Velocity (FPS) Comments
28 2297,2310,2296 ES= 13 FPS.
29 2341,2345,2331 ES=14. Case full to bottom of neck
30 2430,2444, 2438 ES=14. 100% load. Bullet seated on top of powder
31 2499,2491,2508 ES= 6 Compressed load. Absolute Max! Shiny ejector mark

Note1: Geco 124 grain FMJ factory ammo measured 2424, 2430, 2429 fps.
Note2: Hornady 130 grain spire point bullets with 30 grains of AA1680 chronographed 2750 FPS.

This cartridge definitely duplicates 30/30 performance. It does so with less powder, noise, and recoil. Time will tell if the cartridge will do more when I receive my supply of Lapua brass.

The last 30/30 I tested was a Savage 325 bolt action rifle, also with a 20” barrel. It chronographed 2094 FPS with 170 grain Remington Corelock, 2295, with 150 grain Remington Corelock, and 2365 with Hornady LeverEvolution 160 grain factory ammo. With hand loaded 30/30 ammo, I would call the pair of cartridges ballistic twins, as both cartridges can approach 2500 FPS with 150 grain bullets. Certainly no deer or hog would know which hammer had hit them.

The Howa rifle is a particular pleasure to shoot. With factory loads, it has been no trick to keep 3-4 rounds touching at 50 yards. As the barrel heats, groups open. While this ladder test did not measure accuracy, the minute ES suggest the rifle would delivery excellent accuracy with these loads also. The Howa is definitely easier for me to shoot more accurately than the Savage 325 or any lever 30/30 I have tried.

For those who might be interested I just put the companion barreled action to this 7.62x39 project for sale on GB. It is a 6.5 Grendel with 2 mags, two factory bottom parts and one aftermarket DIP aluminum bottom metal. Very reasonable.

Ive done a couple 338 x 39 on AR and CZ platforms, lots of fun but I like my 375 Grendel a bit better.

Is anyone aware of a Grendel blown out straight? Maybe 10mm or 41 cal bullet?

Thanks