I had a hankering for a micro action chambered for something that would be a little more than the usual suspects and had been increasingly interested in the 6.5 Grendel but thought that there was still a little left on the table as far as capabilities went with the Grendel cartridge. I bought a packet of Grendel ammo and had a couple of 7.62x39 cartridges and wondered what whould happen if the shoulder was pushed forward and it was loaded longer than the Grendel which is hald to its factory COAL because it was designed primarily for the A R platform and consequently loaded to a presure limit that would not be required with a bolt rifle. I had a set of Forster Grendel FLS dies sent over and by putting a .05 spacer die on the shell holder was able to hydroform a case to what I found would give considerable more capacity especially if the 123gn A Max was seated out to a 2.405 OAL rather than the 2.250 of the Hornady round.

Hornady Grendel on left and my Grendel Max on the right



In looking for an action I came across an Interarms mini mauser action bare for about NZ$80 (US$65) and because of my reduced circumstances intended for this to be a minimal cost project. I Cut the back of the magazine and ground out the rear of the mag recess abutment and made a temporu rear mag extension to see if it would all work and instead of running the rear wall of the magazine up past the abutment I ground a housing in the bottom so it would form a continuous face up the back wall and up the face of the abutment and was able to get 2.475 internal length so my projected COAL looked to be a workable length. This length was arrived at with the A Max which would be the primary bullet was loaded with the start of the boat tail at the base of the neck so the next thing was to draw up a reamer print (that would give me a 25 thou jump at my desired OAL) and get it away to Mansons. A light Sako profile 6.5 x 8 twist barrel was ordered from TSE in Australia and at chambering was cut to 21 inches.
The bolt handle was a typical Mark X handle that is really too short with a knob that is too small for easy manipulation so I cut it off and used a piece of 7/8 bolt that I D&T to take a 1/4 in thread, which I then put in an battery drill and held against a belt linisher to bring it to a suitable shape.

Action as received



Bolt handle




From this I expected everything would work as planned.


eeping in mind that this was to be a low cost rifle I decided to make my own laminate stock rather than using w walnut blank as I had for previous rifles so I started with a 16mm central core and planedit down from the action forward to the forend tip and from the actiondown through the pistol grip because I wanted tha main shaping done on the core piece so that the outer thinner laminates would be full length and therefore stronger than the usual way where they are cut through as the shaping is done from the outside toward the centre. The added bonus is that the pattern is cut on the central core and the action can be layed on and the exact outline of the inletting can be marked and cut out with just a sliver left at top and bottom to hole the forend to the wrist and butstock while the remaining laminates are glued on. I used Beech for this as it is very light and very tough, at least the NZ beech is.


I made a smoker for the inletting as I had always used inletting black before but a little used lantern offered a handly wick assembly and after pop riviting a cvouple of tabs on a suitable old tobacco tin had a smoker that could still do service in the lantern housing if and when needed.


After a bit more work I had a lovley light little rifle that even with the Warne steel bases and rings with the Nikon 4.5-14 scope still weighed in at 6 lb 12oz and with the mini supressor stopped the scales at 7 lb 6oz

So then it came time to do some testing and with CFE 223 and the A Max's I did my 200 yd ladder testing with this result.



It seems I had loaded the no 10 shot at 31.4 rather than 32.4 going by the results but It was enough to set the paremeters for the next session


After another trial session I settled on 32.6 gn for an even 2700fps and while the wind was starting to effect the second shot string it is certainly more than encouraging for a light rifle. The velocity gain over the AR Grendel loading has made this a worthwhile project.



So for a minimal cost of NZ$1562 (US$1312) including the supressor (although I did have the Nikon on the shelf) I have got myself a light hill rifle that will perform up to and exceding what hoped for. I have also had a cast bullet mould made by Veral at LBT and will hope to get that into the 2300fps + range for inside 200 yds on the goats etc and a realy cheap plinking round. Had the mould made so that with the same seating stem setting I can go from the cast bullet to the A Max with out adjustment so have a very versatile and uncomplicated little cartridge for a wide range of aplications. With the New SST released to have the same shape and BC of the A max but with an inproved 'on game performance' then this is also a realistic 500 yd medium game round with the rifles ability to get it to the right place

Grendel beside a 127gn cast bullet in a Lapua 7.62x39 case necked to 6.5 and ready for fireforming, and the 123gn A Max in a Hornady Grendel fireformed case..



And I may just have to change my sig line

I wonder how easy it would be to adapt this round to a Kimber 84m Montana? I've thought this rifle in a 260 rem or 6.5 creed more would be ideal in terms of light recoil, good accuracy and great penetration in an ultralight all weather rifle. This round might be even better for this application, although there are obviously no flies on your custom! Great concept, and thanks for sharing.
M

This is the reamer print I drew up Matt and it should be on file at Mansons. I made up a cartridge and the GS used the "just kiss it with the bolt to HS the barrel.

Gidday Von Guff

You really have excelled yourself on this one - I was hoping to see it on Sunday but alas events (and women) conspired against me.

I'll give you a ring this evening or tomorrow.

Cheers

Very interesting Von Gruff.

Thanks for posting.

I don't know about the rifle. It seems very nice. However that is the most beautiful shooting range I've ever seen! And I an thoroughly jealous!

Seems to group quite nicely. You got a steal on that action.
Could you post a pic or two looking down into the back of the mag from above? I see the box extension, but can't picture some of the other details of what was done to the action in this area. I have two of these I am slowly working on, a 30BR and 30 Grendel Imp 40*. If I could gain .150-.200" in loaded length, it would be a significant improvement and worth hacking into the mag box.

This is as clear as I can get it but normally the rear mag wall runs up in front of the abutment. You can see the small recessed housing where the rear mag wall now runs into so there is still a continuous face up the inside of the mag wall and the top half of the abutment. Not as clinical as a mill would do it but with just a dremel it is still a solution within budget and gives 2.475 inside measurment to the mag. Of course you loose the screw fixing of the mag to the bottom metal but a good tight inletting solves the need for fixing it the BM anyway.