I am having a Mosin Nagant day ... 300 Win Mag

[Clark]

I am building a 300 Win Mag Mosin Nagant.
I have it chambered and stocked.
Now I am working on getting it to feed.
I did this a year ago with 7mmRemMag, but I forget what i did. That was with a Rem700 take off. This one is with a new Krieger barrel, so it is getting some baby pictures [so I can remember].

[F. Guffey]

Clark, thank you for sharing, I did not see a question so I will assume you are well on your way.

F. Guffey

[skizzums]

Please upload some pics of this thing. Very excited to see what you've done. I am trying to figure out the best way to configure a 6.5x53R mosin. After talking with a couple custom barrel makers and shopping stripped receivers, it seems like it's possibly more affordable and easily achieved than I first thought.

[tobnpr]

Clark,

What about the mag? That's one hell of lot of real estate opened up.

Far a 6.5 x 53R (for all intents and purposes, same as 54R) you'd need a custom reamer made- as well as custom reloading dies, but other than that it would be just as straightforward as a .308 re-barrel where no modifications are required to the receiver or boltface, retaining the original cartridge except you're necking it down...

Waaay down, my guess is that will take several steps.

[leadcounsel]

Hmmm... ruining or experimenting with a $200 Mosin, spending hours doing it, and a caliber it was not intended for... and probably at least a hundred or a few hundred in supplies/parts.

Or ...

Buy an off-the-rack Savage .300 win mag for $400-$500 (or used for less), and have two guns.

Simple choice for me... but good luck!

I suppose if it was damaged, I could see it... but why not just re-chamber in a smaller caliber. Can a 100 year old action withstand the .300 win mag? A bolt head to the face would make a poor range day...

[Clark]

I milled out the inside of the mag well:
1) In front with a small diameter end mill that matches the radius already there... just make it longer.
2) I milled out the rear of the mag well the same way, but I had to file the corners.
3) I milled slots in the sides of the mag well to make room for the belt on the cases and the big long shoulders.

I made a dummy 300WM round that was 0.015" over the 3.34" standard. I really hate it when things don't fit when I am hunting.
Where the dummy rounds get scratched I went back and polished the feed lips and ramp bevels I made yesterday.

This is a fancy stock and fancy barrel 300WM Mosin. Last year I made a cheap stock cheap barrel 7mmRemMag Mosin. I kind of forgot how i did it. Good reason to post the 300WM here. I am having to reverse engineer my own stuff. And in one case do better. The ejector over ride switch made of 1/8" carbide with plastic collar for the 7mm is being replaced with a 0.134" galvanized finish nail that I turn down with sandpaper to 0.125". The plastic collar might come off. The nail head will not come off. I need this button so I can unload unfired rounds. I do not want to open the ejection port for 3.34" ammo as the front and back of the port are camming surfaces for the bolt. Without the button the extracted unfired bullet tip gets trapped in the front ring.
You can see I made thumb nail cut into the nail head for disengaging the ejector override.

The back of the recoil lug is modified to 90 degrees to fit the toilet shaped front pillar structure.

The ATI mount is drilled and countersunk for a 3rd 10-32 hole.
The ATI mout captures the nail.

[Clark]

Lead Council,

And when I measure the bolt lugs and calculate the lug cross section area in shear:
Mosin Nagant 0.414 square inches
Savage 110 0.396""
Remington 700 0.387""
Win M70 0.376""
96 Mauser 0.325""
98 Mauser 0.313""

When I run 7mmREM in an old 98 Mauser with 110 kpsi QL, the lugs and abutments start to show plastic deformation.


That particular Krieger barrel was scrapped out for $103 instead of Krieger custom mega bucks because of the wrong thread pitch on the muzzle. 1/2-24 threads on the muzzle.
No brakes have that thread. They are all 1/2-28 or 5/8-24.
I made a 1/2-24 muzzle cover

The other end of the barrel, the breech had some kind of small action threads. Of all the types of actions I have waiting in the wings that would work were 1938 Turkish Mausers, Rem #5 rolling block, and Mosin Nagants.

Today I drilled the stock for Uncle Mike's sling swivel studs.
I pulled off the old Winchester /Pachmayr pad and put on a large grind to fit Limbsaver, but did not grind it, wanting to keep more area.

I cut off the sharp corners of the ATI scope mount with a deburring wheel.
It is ready to shoot, but I can't decide which scope to mount on it. Probably either a VX3 CDS 3.5x10x40 little lightweight thing or a big heavy 4x14x50 IOR.

[tobnpr]

Interesting that you milled a combination pillar/cross-bolt for the recoil block.
Not sure that aluminum serves the purpose of absorbing/spreading the recoil forces any better than solid epoxy bedding would- but that's a neat idea

I had noticed some time ago that the recoil block on the MN receivers was so far out of square to the bottom of the receiver it was a joke- they look as though they weren't even intended to be...

Given that it's a "must" for recoil lugs in accurized modern rifles to be perfectly square to the receiver/boltway and 90 degrees to the bore, I began milling mine just as you did. I've never read about others doing this- but I cannot believe that these out-of-whack recoil blocks don't affect accuracy. Recoil force of a canted recoil block against the stock will want to lift the action out of the stock- instead of transferring it straight to the rear into the wrist of the stock as it should.


ETA:
You use a mini-lathe for a grinder?

[BumbleBug]

Clark,

I always enjoy your projects. Hope you post the results of this conversion - it should be interesting!

...bug

[Clark]

Yes, the Griz mini lathe I got in 2002 really sucks as a lathe. It can chamber pistol barrels but the crossfeed and compound are worthless. The 3 jaw chuck is a quick change for wire wheels on mandrels. Get it far from me on a deep bench and perpendicular, and I have never been hit with flying debris. I can't say that for the wife with a weed eater.

I have 3 rifles chambered and ready for the range. They do not have any paint, bluing, sanding or other appearance stuff done. The last time I made rifle beautiful before I shot it, it turned out to be a 2 moa 260.

1) 1903 Turkish Mauser Douglas 12" twist barrel 6mmRem, Boyd's pro varmint stock, Karsten's custom cheek rest model A, Harris swivel bi pod, KMW pod lock, large aluminum round rear pillar, long rectangular recoil lug/front pillar, TIG welded extender bolt handle, #S45 rear scope base milled on the underside to fit, USO 1.8x10x37 scope, Bold trigger with safety, and SWFA tactical rings. I have 100 rounds of ammo loaded.
2) 2015 Dumoulin Mauser Shilen select match 8" twist ratchet rifling 6.5-06 Boyd's pro varmint stock, Karsten's custom cheek rest model A, Harris bi pod, KMW pod loc, large aluminum round rear pillar, long rectangular recoil lug/front pillar, sling stud mount [really long], Limbsaver large grind to fit pad unground, #S46 and #S54 Weaver scope, Bold trigger without safety, bases milled flat on the bottom and glued *, Sightron SIII 3.5x10x44, Weaver tactical rings 48355. I have 200 rounds of ammo loaded.
3) 1939 Mosin Nagant, Krieger stainless with black finish,300WinMag, Walnut stock, large rear round aluminum pillar inletted for Timney trigger, front pillar/recoil lug shaped like a toilet and made of Aluminum, Harris swivel bi pod, Alpha bravo pod loc, Uncle Mike's sling swivel studs, Limbsaver large grind to fit pad unground, Leupold VX3 3.5x10x40 CDS, Millet angle lock rings, homemade muzzle protector, galvanized nail as ejector over ride button, milled out magazine box for belted magnum length and width, TIG welded bolt handle extension, ATI scope mount modified for 3rd hole, I have 50 rounds of ammo loaded.



----------------------------------------------------------------------------------------------
* Why were my scope bases getting loose?
Typically two Weaver scope bases and each base has two 6-48 screws.
Grade 5 bolts are good for 127 ksi in tension
6-48 screws have a 0.12" root [minor diameter]
Area of a circle = pi r squared = 3.140(0.120/2)^2 = 0.0112 sq in
Tension = area times stress = .0113 sq in 127 kpsi = 1456 pounds tension per screw
There are 4 screws = 5745 pounds potential clamping force.
The screws are only loaded up typically to 50% of rating = 2873 pounds total clamping force on the two bases.

If I look in quickload at the 6.5-06 I just built with a 142 gr Nos Bal tip Long range bullet accelerates from 500 fps to 2000 fps in 0.4 ms.
The bullet weighs 142 gr = 142gr/7000 gr/lb = .02 pounds
The rifle recoils proportionally slower.
0.02 pounds / 8 pounds = 394 times slower than the bullet.
500 fps / 394 = 1.27 fps
2000 fps/394 = 5.07 fps
An 8 pound rifle in recoil reaction would then accelerate in proportion from 1.27 fps to 5.07 fps in 0.4ms
acceleration = change in speed/ change in time
[5.07fps - 1.27fps ]/0.4 ms = a peak acceleration of 9500 ft/sec sec
If a 2 pound scope were attached to a 6 pound barrelled action and stock they would act as an 8 pound single mass.
The mass of the 2 pound scope is = [weight]/[gravity] =[2]/[32 f/ss] = 0.0625 slugs
Force = mass acceleration = [.0625 slugs ][ 9500 ft/sec sec]= 594 pounds of force pushing back on the scope in recoil

The Mausers I just built is made of steel, as are the modified S54 and S46 bases.
Looking up the coefficient of static friction of steel on steel:
https://en.wikipedia.org/wiki/Friction

Case #1) 0.74 ~ 0.80 for dry and clean steel
Averaging the two would be 0.77 coefficient of static friction clean steel on clean steel
The static friction force threshold of slipping = [coefficient of friction clean steel][clamping force] = [.77][2873 pounds]= 2212 pounds force threshold.
Because the static friction 2212 pounds is greater than recoil reaction on the scope mass 594 pounds, the scope bases should not slip on the reciever.

Case #2) But the coefficient of friction for lubricated steel on steel is 0.16
The static friction force threshold of slipping = [coefficient of friction lubricated steel][clamping force] = [.16][2873 pounds]= 459 pounds force threshold.
Because the static friction 459 pounds is less than the recoil reaction on the scope mass of 594 pounds, the scope bases should slip and the screws should start shaking loose.

[Gunplummer]

Leadcounsel, Sometimes I think it is just fate taking a hand. I picked up an MAS 36 at a show that was really beat (Probably a VC bring back) and chopped up. I bought it mainly just to study it because I never had one apart. I kind of looked at it and thought maybe turn it into a 20 gauge slug gun? I asked a couple guys at work if anybody had a 20 gauge shell laying around that I could use to check dimensions. No one. That Saturday I was bow hunting in a thicket and found a loaded 20 gauge shell laying on the ground. If that was not fate, I don't know what was. It was the start of a longggg build. As always, the feeding was the worst of it. I finally settled on a spring out of an old Mossberg shot gun magazine. I tried a few different ones until I found one compatible with the lighter slugs for rifled barrels. In the end, it holds two in the box and one in the tube. My buddy (Lives in a shotgun only area) has killed two bucks and a couple does with it.

Was it worth it? Heck no, but it is an itch some people have to scratch. I get why Clark does it.

Is that a Richards Micro-fit stock? I used to buy a lot off him, and it looks like his work.

[F. Guffey]

Is that a Richards Micro-fit stock? I used to buy a lot off him, and it looks like his work.

Twice, that was the first and last time. I told them I thought I could train woodpeckers to do a better job. I know, there is a difference between a micro fit and a club.

F. Guffey

[Clark]

I went to the range and shot the three new barrels.
Usually new barrels shoot well, but not today.

---------------------------------------------
Mosin Nagant 300 Win Mag:
3189 fps
3093 fps
3159 fps
Quickload predicted 3189 fps 64 kpsi 150 gr Nos Bal Tip moly 3.34" 24" barrel, I used the QL library data for H322, but it is really 1960 military 4895 pull down with the same density and speed as H322 powder, but the grain size and shape is 4895.

At 50 yards, shooting 3 shot groups:
6.0"
1.7"
0.2"
-----------------------------------------------------------
1903 Turkish Mauser 6mmRem
Made dents in the primer, but none went off.

-----------------------------------------------------------
2015 Dumoulin Mauser 6.5-06
2982 fps
2956 fps
2873 fps
Quickload predicted 2977 fps 67kpsi 142 gr Nos Accubond long range 54 gr H4350, 3.34" 24" barrel
50 yards 5 shots 1.1"
100 yards 3 shots 1.2"
100 yards 5 shots 2.8"

[Hunter Customs]

Gunplummer, the day you found the 20 gauge shell might have also been a good day to buy a lottery ticket, it sounds like your lucky stars, the moon and planets was aligned right.
Anyway it all worked out as the 20 gauge shell got you into a knew project.

Clark, keep up the work I always enjoying reading about the things you are doing, no matter if it's reloading or gun builds.
When it comes to firearms many such as yourself have done things that were not cost effective and they helped get us to where we are at today.

Numerous times I've made things that if I figured my time they would not be cost effective, but I truly enjoyed doing them anyway just because I could.

[Gunplummer]

It may be an affliction. I pretty much sold out and moved to a smaller place, but in a few years I have accumulated a bunch of parts guns, piles of parts, and probably a dozen barrels. At least I did manage to stop the bow collecting.

[tobnpr]

Usually new barrels shoot well, but not today.

A .2 inch group, at 50 yards- is certainly impressive.
If the listing was in order (worst first, best last) looks to me like the barrel's just getting broken in a bit- maybe some minor imperfections in the leade (if it wasn't lapped) and it's just laying down a baseline of copper fouling.

If that .2 holds ( under 1/2 minute), you'll debunk the old "Mosins can't shoot"...

Do you have a Timney trigger on it?

[Clark]

I am looking at the last group the rifle Mosin shot, the 0.2" group like a hanging chad.
Either it is a 3 shot group [seems very unlikely] or one of the three shots missed the whole target [seems very unlikely].
What would Sherlock Holmes say?

I have the Timney on the Mosin and Bold on the two Mausers.
Until this week I had no reason to think Timney was worth the extra money, but adjusting the Bold... I want to get a bare bones Timney for a Mauser for a comparison side by side.

[Clark]

I figured out why that 1903 Turkish Mauser 6mmRem firing pin was not getting the job done.
The bolt was not closing. I had not relieved the bolt handle where it was welded and would interfere with the receiver. And I had to cut away at the stock.

I got an extra long end mill, but the mill spindle dug into the bolt handle ball.

I used a deburring wheel, and it washed my mistakes away:
https://www.use-enco.com/CGI/INSRIT?PMAKA=MK317-1741

[Hunter Customs]

Clark, not trying to second guess your work just wondering if there may be a concern for stress risers on the square cut of the bolt handle?

[tobnpr]

I think it'll be fine, stuck bolt that needs to bashed with a mallet, maybe not...but it doesn't (or shouldn't) take much force to simply run the bolt under normal circumstances. Besides, I'm sure Clark has run the "numbers" with his usual engineering expertise

When it comes to the Mosin-Nagant, which is my bolt "niche"- I fabricate them differently, but all others I'm aware of make a low-profile (clear a scope mount) by milling off the entire handle. The top of the bolt body flat is such that there's very little clearance with this method to the scope mount- with many using CNC'd handles that are barely a twig. I've not heard complaints of them failing (bending), but they're not substantial enough for me.

I had a customer return one of mine that I agreed to mill out to work with his mount (my standard is the ATI for clearance, his was MUCH lower)- and I had to mill the top of his handle to just .0225- which is all I could give him, and he STILL needed to mill out the bottom of his rail a tiny bit.

Fortunately, Clark's rifle didn't fire with the bolt partially out of battery.

[Clark]

Ever shoot with guys who killed a lot of people in Viet Nam?
Big stressed out guys?
I saw one in 1995 clear a jammed FAL by jumping on the cocking handle like he was kick starting a Harley.
Like a one leg pogo stick.

So there is more than one way to break off a bolt handle.
I think the Gold standard in wimpiness is the Rem700 soldered on bolt handle. When they break off you can see.. not very well soldered on.

I think I have enough 1903 Turk bolt handle weld area left that squeezes between the scope eyepiece and the receiver to support me in shear if I ever do the pogo stick move.

Jack Belk [pres of the gunsmith guild] posted some pictures 15 years ago on TIG welding Mauser bolt handles. I saved those pics. Back then a lot of guys were notching out the receiver, as does the Dumoulin. That avoids these questions about not enough metal left on the handle. I would rather leave the receiver alone.

[Hunter Customs]

Thanks for the response gents, as I said I certainly was not second guessing Clark's work.

[Gunplummer]

Reminds me of a younger guy that was doing a rebarrel and sporterizing a 99 Arisaka for himself. The bolt handles are pretty thin where they contact the receiver. Anyway, he brought the gun to me and said in about 6-7 test rounds, the cases were getting longer (Losing headspace). What was happening was the welded area had contacted the little notch in the receiver when he cut the chamber. The bolt lugs were not touching at all and he headspaced off the bolt handle. The weld started to compress and he got a form of "Setback".
I think the bad bolt stories are mostly left over from gas welding days. I have seen some really nice sporters with a crappy weld on the bolt handle. Some even have porosity in the weld. Nothing wrong with gas welding, but it is a different skill level.
The lousy Remington bolt handles are just poor brazing (Or silver soldering). You can see the tape did not attain enough heat when they pop off. Take a hammer and try to beat a piece of carbide off a large stick tool. Ever try to pound a sight base off a Mauser barrel? That is only soft solder.

[Clark]

I have taken the rear sight off a Mauser. Joe at Realguns was trying to restore and re blue one. I had lots of take off barrels so I experimented for him. I heated it up and hit it. That looked like a really good solder job when it came apart.

I am trying to get ready for the range AND visit the grandkid tomorrow.

[Gunplummer]

Yes, they come right off with heat. One would think the solder would break down over the years on those Mauser barrels, but apparently not.