New 6mm With Mausingfield Action

This is my new build. It is a 6mm Comp Match, a modification of the 243Win similar to the 243 AI but retaining the original taper and having a 37 degree shoulder.  The chamber is made by Long Rifles Inc. in Sturgis, SD. The cartridge can be fire formed from a 243 Win cartridge (in the pic to the right of the loaded 6CM) by the method I described in another post (see" Deck's 7mm WSM Brass Problem Solved")  The gun can shoot the new experimental 96gr PICBM (Jason thinking again) bullet (G1BC 0.545) using Retumbo at or beyond 3200 fps.  The Mausingfield short action is super smooth, has controlled feed and will accept single feeding without putting the shell in the mag first. The stock is a $250 Magpul 700 Hunter stock. I dropped right in with only a slight amount of inletting to allow for the side mounted bolt release.  The funky looking bolt handle is quite comfortable and functional.  Magazine is an American Rifle Co. 10 round center feed mag that will fit any AI Magazine compatible bottom metal and will accommodate 2.955" OAL ammo.   The Muzzle brake will fit Thunder Beast suppressors. Mine works great with the 338 Ultra which I can use in my 308 or 338 rifles as well. Still in load development but the rifle is capable of 1/4 MOA groups.  Barrel is a K&P 5R 1:7 twist barrel.  This cartridge/bullet combo has a flatter trajectory and better windage at 1000 yds than a 260 Rem shooting a 140gr 0.6 G1BC bullet. Barrel life is supposed to be around 3000 rounds. Perfect for Antelope

Edited by nralifer - December/20/2017 at 19:33

Really nice rifle, George!

Sounds like a really great rifle.  I've been wanting a Mausingfield action rifle.  I just can't decide what I want it to shoot (caliber).  

Sounds like a nice build. Question on bullets: why do you and Jason only list G1 BC values? It does not seem to be a good predictor of downrange trajectory with modern bullets. G7 seems to work better.

ILya

We are going to get individualized drag curves for some of the ICBMs. The weird thing is that at at low Mach numbers drag starts to increase then drops off rapidly as the bullet becomes subsonic. One guy told us that for the 250 SICBM the BC we quoted he thought was low since he was hitting high at 1750 yds. A rough estimate of G7 BC is half the G1 realizing that below Mach 1.4 the Von Karman function governing the ogive shape of our bullets is more efficient at low Mach numbers that are the secant or tangent functions.

One thing about the Mausingfield is that if you can bare to use a barrel nut you can use barrels threaded for Savage actions. If you are conflicted about calibers get barrels for both👍

nralifer wrote: We are going to get individualized drag curves for some of the ICBMs. The weird thing is that at at low Mach numbers drag starts to increase then drops off rapidly as the bullet becomes subsonic. One guy told us that for the 250 SICBM the BC we quoted he thought was low since he was hitting high at 1750 yds. A rough estimate of G7 BC is half the G1 realizing that below Mach 1.4 the Von Karman function governing the ogive shape of our bullets is more efficient at low Mach numbers that are the secant or tangent functions. One thing about the Mausingfield is that if you can bare to use a barrel nut you can use barrels threaded for Savage actions. If you are conflicted about calibers get barrels for both👍

It simply is the most versatile bolt action there is, and is the one that will maintain the bullet as perfectly aligned to the bore centerline as possible.  Anything with a plunger extractor puts an eccentric force on the cartridge so if there is space there will be some misalignment to the cartridge.  If you can stand a barrel nut, changing barrels is a 15 minute process, so if you wear out a barrel, no gunsmith bill needed.

Edited by nralifer - December/20/2017 at 19:34

Lori won't care.  

I actually spoke with Lori about this… she wanted to order me one for Christmas.  I explained that it would take a little more time than that to meet my complete set of requirements for building this rifle.  Now I'm on the hunt.  

nralifer wrote: Ha! I knew you liked the 338-06  You will like it even more shooting these high BC all copper missiles in the AI version from that long, silky smooth, superbly aligned, tuned, flawlessly feeding and accurate Mausingfield. The 225gr Bulldozer and the 234 ICBM (BCs 0.64 & 0.66 respectively) will have more energy at 300 yds than the 6.5 Creedmoor has at the muzzleDeadly

nralifer wrote: It simply is the most versatile bolt action there is, and is the one that will maintain the bullet as perfectly aligned to the bore centerline as possible.  Anything with a plunger extractor puts an eccentric force on the cartridge so if there is space there will be some misalignment to the cartridge.

I’ve heard that mentioned as an “advantage” in favor of actions with fixed blade ejectors many times, and conceptually the argument makes sense. However, I don’t buy it. I’ve got no shortage of actions using both ejector types, and if that made a difference, I’ve never been able to see it on targets. Lots of benchrest competitions have been won with plunger ejector actions. If you think about it, plain ol’ gravity has the same effect. Instead of the case leaning toward the side of the chamber in response to plunger spring force, gravity makes the case ride the bottom of the chamber.

I prefer a blade type fixed ejector simply because I can control the case ejection force and distance by how forceful I work the bolt. But as with most things in life, gaining one advantage usually involves making some negative concessions. A fixed ejector system is slightly less safe in the event of case rupture, because it requires a slot through the bolt head that gives gas an escape path back toward the shooter.

The Mausingfield is a cool action, but damn, I wish they’d used a bolt knob design that didn’t look like a Christmas tree ornament!

That's the reason I like it… I have Christmas tree ornaments exactly like that (different color).  I may paint it if I get one…

I guess that’s why they still make chocolate & vanilla isn’t it.

or vanilla chocolate...

        

I just gotta say why a magpul stock? Such a beautiful setup and then that stock. Just a little ribbing is all ;).

supertool73 wrote: I just gotta say why a magpul stock? Such a beautiful setup and then that stock. Just a little ribbing is all ;).

Agreed 😂

More for practical reasons. I needed the gun quickly because we were developing more bullets for the 6 mm caliber. I could get the barreled action done in 2 weeks but would have to wait 6 -8 weeks for an inletted Manners stock. The twist needed for the new bullets was going to be 1:7 and my friend, who sells for LRI in Sturgis, had a 7 twist barrel available. As it turned out I like the Magpul stock. It is adjustable for cheek rise and LOP, and has a stiff forend sufficient for a bipod. It is a real value for the money. The action dropped right in save for a very minor inletting to accommodate the side mounted bolt release. Also, once sighted in, removing and replacing the action in the stock did not affect the point of impact.  Jason just finished the prototype bullets today (100 gr Bulldozer and a 105gr ICBM, both with BCs that we think will be higher than the 105 Berger), so I will have the chance to shoot them this weekend if we don't have a blizzard. The gun is capable of 1/4 MOA or smaller accuracy.

Edited by nralifer - December/19/2017 at 23:05

Lori gave me a "thumbs up" on the Mausingfield in 338-06 with a Cadex chassis.  There are some specifications to work out, but looks like I'll be making some orders sometime after the first of the year.

I'm seriously thinking of painting the the bolt knob in Christmas tree decoration colors...

I love my Mausingfield. Built mine in 22-250. Have a second action sitting in my safe if anyone want to buy it. Or until I decide what else to build.

Should be an AWESOME 338-06, especially the bolt knob.   

Peddler wrote: supertool73 wrote: I just gotta say why a magpul stock? Such a beautiful setup and then that stock. Just a little ribbing is all ;). Agreed 😂

This^   Rifle is a piece of art. Then put it in that stock. One of these days I'll talk him into good stocks.