reloading for the Johnson

[woody 0]

Are there any constraints on powder, bullet weights, or anything else when reloading for the Johnson? The M1 requires powder with a specific pressure curve such as IMR 4895 or IMR 4064, and bullet weights of 175 grains or less to prevent damage to the operating rod. Do the same constraints apply to the Johnson?

[keith smart 0]

Are there any constraints on powder, bullet weights, or anything else when reloading for the Johnson? The M1 requires powder with a specific pressure curve such as IMR 4895 or IMR 4064, and bullet weights of 175 grains or less to prevent damage to the operating rod. Do the same constraints apply to the Johnson?

I think the Johnson is designed for M2 ball (works great). In fact, the left side of the rear sight base is marked M2

[woody 0]

Keoth is corrcet. Oroginally the JSAR was calibtarted for M1 ball but when US Ordnance changed the spec to the M2 ball round the sights were recalibrated fior that round.

Any loading data that replicates the M2 spec should work fine. I use 4895 and have had good results in all my . US military 30-06 rifles by using it.

Thanks. I've been loading 46 grains of IMR 4895 with the Sierra 168 gr. Matchking for the Garand. Does that sound suitable?

[webmaster 0]

Sounds OK. If it works in an M1 Garand it should be OK for JSAR. You may have to tweak it slightly to get a round that is good for your rifle.

[ryche_me 0]

Thanks. I've been loading 46 grains of IMR 4895 with the Sierra 168 gr. Matchking for the Garand. Does that sound suitable?

Keep your bullet weight around that grain weight. I made the mistake of shooting some federal 180 grain HI-SHOK in mine ,the recoil just about knocked me over.I was afraid if i fired any more i might damage my rifle. After going back down to the 150 to 160 range it was alot better.

[woody 0]

Thanks, guys. That load works well in the Garand and it will really simplify things if I can use the same load in both weapons.

[cdj7097 0]

Keoth is corrcet. Oroginally the JSAR was calibtarted for M1 ball but when US Ordnance changed the spec to the M2 ball round the sights were recalibrated fior that round.

Were the sights recalibrated for all JSAR's?

[Adriaan de Jong 0]

The rearsight of my Johnson has M1 stamped on it....

Adriaan

Sorry made a mistake, it has M2 on it.

[ArtR 0]

As this thread is about reloading, I feel that I should bring up one point that has not been mentioned and seems to be lost in many load books.

That is the difference between military and commercial brass. I am not so sure that it is of consequence with much of the current issue military, but most of the pre-80's military brass, and there is plenty out there as evidenced by surplus sales, was of heavier and different design than commercial brass. Much of the earlier military brass was heavier in construction, thus had less volume available for powder. Putting too much powder in the reduced volume could increase pressures above acceptable levels. Many of the good load books will either have a special load page for military brass, or at least will note that when using military brass that reloader's should use reduced loads to start, with reductions being as much as 10%. That is to say, if the load page did not specify that it was for military brass, if the starting load for commercial brass was say 41.5 grains of IMR 4895, if you were using military brass you would start with with 37.3 grains.

That being said, here is another caveat. Never start any new load with a maximum charge....by that I mean, if you have changed lots of either brass, powder, primers, you should go back to the load table starting at minimum and work up to the load that works best for your rifle.

I never mix brass lots! Period! In fact I do not mix brass shot in different rifles, but that is Just a thing I do. But hey, we are all entitled to our quirks. My point is, if I have 100 rds of brand X brass and 200 rds of brand Y that I have shot, they are never added together. They are always in their own separate containers and kept that way. Using loading logs and lot numbers will assist in keeping this all in order.

[M48TANKER 0]

Gosh, we've got a lot of knowledgeable folks on here. I've only shot 30.06 commercially loaded rounds in a Remington 742 hunting rifle, and my experience with Military surplus 30.06 is limited to machine guns, mainly 1919A4s and they'll eat most anything. What is the consensus on CMP ammo? Which of their offerings is best for both rifles, M1 Garand and the 1941 Johnson? I've heard good things about the Greek HPX ??? and CMP sometimes has AP ammo for cheap too..sold out right now I think. Different lot numbers and years are corrosive, so I'll learn to look for those. I've shot so much corrosive ammo in the machine guns that the cleaning drill is just SOP to me now...all my guns get a through cleaning within hours of the shooting session, just to be sure. M48TANKER

[woody 0]

HPX meets the specs for M2 and shoots well in the Garand. Haven't shot it in the Johnson so I can't comment on that but suspect that it should be fine. That said remember that it is garden variety military ammo so don't expect tack driving accuracy unless you get lucky.

The last I heard the CMP AP is corrosive and I believe it is sold out. You might want to check their website for an update though.

[ArtR 0]

While I cannot verify AP, I know that all US, NATO, and most all Greek, Korean, and Israeli .30-06 was loaded to M2 specs, for use in M1's, thus should be suitable for the Johnson. I have recently fired Korean and Greek in my JSAR and it functioned exceptionally well, but I cleaned the weapon well afterwards as I was not sure on corrosive nature of ammo.

As for reloading for M1's, I load to 2700fps, or slightly slower, and try to keep pressures down. That is, if there is a choice between loads with similar velocities, I go for the one with the lower pressure.

Have fun!

ArtR

[Mitch J 0]

I reload also to M2 specs.

Works great for me.

Wish we could get some animation of the JSR like this..http://www.dav32.com/feeding.html

[Barry in IN 0]

From what I've seen with my lone JSAR, it is really forgiving about what will operate it.

The first time I shot it after getting the barrel back from Mr Scott, the new parkerizing made the barrel extension and guide a tight fit in the radiator. The return spring wouldn't quite return the barrel on it's own when worked manually until the park got shined up a bit. I was at the range without Scothbrite or anything, and eager to shoot. It was then that I realized I had brought no M2-level ammunition and only had some lighter loads (155s at what turned out to be 2550 fps).

I thought there would be no way it would work, but I tried it anyway, expecting to run it manually.

It worked fine.

That encouraged me to try cast bullet loads just to see how light of a load would operate it, and I got it to work (feed, function, and lock open when empty) with 180 grain bullets at under 2000 fps, and 165s at just a little faster. That's quite a reduction from M2-level loads, and it impressed me because it made me think it would operate if the action was dirty enough to operate sluggishly or if it got a faulty weak round.

[Gman 0]

I've only been reloading for a few months and still learning - and there is a lot to learn. First, I have to agree that military brass is stronger than commercial. While trying to develop a good load for my Johnson earlier this year I was shooting different types of used military brass as well as some brand new Remington brass that I had full length resized (now I know better than to do that). The loads were the same in each: 46.4 gr IMR4895 behind a 168 gr Hornady AMAX. My groupings were not going well with the mil spec brass so I loaded a shiny new Remington. That was the last round I loaded that day. Oh, I forgot to mention that I was using my chrony at the time. Anyway, the last bullet went through the chrony at 2662 fps, the case tore apart in the middle leaving the front half in the chamber while the back half was jammed sideways by the bolt. Thankfully the bolt didn't cycle fully and try to jam another round into the chamber.

That's how I learned about the importance of headspace and why you should resize your cases to fit your particular chamber. The lugs on this rifle had been hammered pretty badly (hunting loads?) so I had them cleaned up and polished by a gunsmith. He advised me that the headspace was right at the no-go point. One thing I was trying to accomplish was to see how much the brass stretched. This led to my purchase of an RCBS precision mic, p/n 88324. If you reload you probably should have one. For comparison purposes I have measured before and after firing some milsurp brass to see how much it grows.

In this rifle, the brass I shot before the bolt was dressed grew about .006 on average. After the bolt was dressed the brass grew about .010 on average. That, coupled with my full length resizing caused the case to fail, in my opinion. I have since replaced the bolt with another that looked practically unused and my cases now grow only about .005 which is right in the middle of the ANSI specification.

I've attached a couple of photos of the mic with loaded ammo inside to illustrate what many of you know already: some commercial ammo is headspaced a little short while military ammo is a little long. The Winchester round is about -.002 under the minimum ANSI spec of 2.0487" while the HXP is .002 over.