Project 300 ack. mag.

baltz526 · Oct 24, 2014

Picked up an Old Custom In 300 ACK. MAG. 26" stainless 6 groove Sporter taper. Inter Arms Mark X 300 HH length action. It is a Chamber based on the 300 HH case. The Bolt is missing, So I have begun a search. I have A bolt that fits Out of My 7mm rem mag But Just as a Limited use option. It has a Action date of J 283 Which Is not the normal Date code marking on Mark X actions. 283 Is generally February 1983 But With the added J I am not sure. Serial is A258XXX. It has a Additional 3 digit on the tang, Which I am also not used to seeing. 337 Which is not part of the serial. It has a single 6 on the bottom near the action lug. Gun Parts Corp lists the Magnum Bolt body, But is out of stock. A few more data points, Max Over All length Of loaded cartridge is 3.600" A 150gr Hornady #3031 Touches the Lands at 3.600". If I center the Crimp groove and measure OAL I get 3.585". Bullets will need to be seated deep to cycle correctly.

NWBlacktail · Oct 25, 2014

I was eying that thing myself. It was a great deal, but will be a bit of a project.

Have fun with that one! It's gonna be cool. :mrgreen:

SJB358 · Oct 25, 2014

Cool project! I almost bought a Pre64 chambered in a 300 ICL, which I think is pretty much the same as the Ackley Magnum, which is just about like a 300 Wby with sharp shoulders right?

Either way, can't wait to see the pictures.

taylorce1 · Oct 25, 2014

Check Gunbroker they have complete bolts from time to time. Interarms, Charles Daly, or Zastava should all work, but make sure to check headspace.

baltz526 · Oct 26, 2014

One Standard bolt face yesterday on Gunbroker. Complete $125. I think it could be Milled to Magnum Bolt Face then Find a Magnum Ejector Or Cut Standard Ejector back. I'll keep looking, There will be the right one out there. I Have 2 loads ready to fire form to get the exact chamber dimensions. I also have a Chamber drawing for the Die set I believe it is. 300 Ackley Magnum #2. Head Space Test using My 7mm Rem Mag bolt looks pretty good. Got a good strong line right at the Neck, Shoulder junction. Pretty thin mark, But it is completely around case evenly. Used Sharpie to Blacken case then cycled case it. No real Confirmation of headspacing on Magnum case base, Just shoulder. Bullet fit For neck length and max ejection/magazine length is looking like a 165gr Like the Ballistic tip, Is what it is set up for. To get the max useable powder space. Volume will be a duplicate of the 300 weatherby From what I can see. + - a few grains.

baltz526 · Oct 26, 2014

Barrel Is In very good condition, Cleaned up real easy. Very little copper fouling. Match type finish on barrel and Chamber is finished at a super high polish. Smoothest chamber I have ever seen that was not Chrome. Action was squared. Trigger is a very good fully adjustable. Not the standard Mark-X adjustable I have seen before. But No markings. This Rifle Probably Left the factory as a 300HH. It was in a Hogue Over molded stock With a nice Custom Walnut stock fully bedded with it. It is now in the wood stock and will stay there. If Anyone wants A Long Magnum 98 Mauser Hogue stock, Just ask. I'll get it to you cheap.

Guy Miner · Oct 26, 2014

Seems you've got a really neat project on your hands! Should prove to be a great hunting rifle once you've revived it!

baltz526 · Nov 2, 2014

Try a picture of what I believe it is,

baltz526 · Nov 3, 2014

Found A Bolt on Gunbroker this AM. USPS MO is going out today. I should have it when I get back from Elk hunting the 17th. Or shortly after. Still need the Weaver scope Mounts, Rings I prefer and a Scope. Leaning towards a Nikon 4.5-18x40 But I might just wait for a good used Scope. Found some more 300HH brass to add to my 60 New 9 once fired. Hope Fire forming is not a case killer.

NWBlacktail · Nov 3, 2014

Sounds like it's all coming together! Probably not in time for cougar camp 2015 (I always enjoy your camp threads), but that gives you plenty of time to develop your loads for elk season 2015! :mrgreen:

baltz526 · Nov 3, 2014

I think it will be ready, if I can Swing a decent scope for it. My Parts list is down to Dies and Scope. Everything else is on its way. I have a bunch Of Bullets to test, Lots of H1000, IMR7828, RE22. No RE25 which Might be the best choice.

baltz526 · Nov 4, 2014

OK. I bought a box of cheap 300 Weatherby today ($40) It confirmed it is the 300 weatherby magnum Ackley Improved. I can just shoot factory 300 weatherby to fire form. Also found that I can go to 3.605" oal with the 168gr tipped TSX. The bullet in the Weatherby ammo I bought. Scope is the last real decision. 4.5-18x40 Nikon Is the leader in that search But the 5-20x44 Nikon is also in the race.

NWBlacktail · Nov 4, 2014

wow, curve ball. Sounds like a cool rig!

baltz526 · Nov 5, 2014

The Rifle is actually fairly light. All set up it should come in about 1/2lb lighter than a Factory Synthetic Ruger 300 Win Mag, Stock was a very nice piece of wood, Beat up now but Perfectly serviceable as a hunting rifle. I'll lightly sand it and give it a seal coat. Pictures will come after Elk season when I can Put it all together. I have a 1.75-5x20 Burris to set on it for pictures and first range test. This scope will be on it until I can Afford a more appropriate scope. Gone Elk hunting, Be back the 17th.

IdahoCTD · Nov 5, 2014

I have a .308 Baer and 2 .30-8mm Rem Mag's plus I've had several .30-358STA's (.300 Jarrett). I rarely lost a case fireforming. If your going to use the used brass I'd anneal it first.

baltz526 · Nov 5, 2014

I have 60 new 300HH,45 once fired 300HH and a 20rd box of 300 weatherby. I'll read up on annealing before I use the 45 once fired. Care to share some .30-8mm rem mag Cronograph data?

IdahoCTD · Nov 5, 2014

I shoot 210gr Matrix VLD's with 76grs of R-22 @ 3100fps in one. In the other I shoot rockchucks with 89grs of R-25 and 150BT's at 3600fps. I can't remember the load with 210's but it was using H-1000. The velocity is really close to the .300 Weatherby but with less powder because it doesn't have the crazy long freebore. In my .308 Baer I shoot 85grs of R-22 with a 150BT at 3550fps.