Neck Sizing vs. Full Length Sizing

[marstev]

I am about to begin my journey learning how to reload ammo, and have chosen a bit of a challenge for my first project. I own an Arisaka Type 30 chambered in 6.5mm Japanese. These are decent rifles for what they are, but rarely have matching bolts to their receivers. This in turn leads to head spacing issues as I may have experienced on the day I finally took mine to the range. In addition to a bit of sloppy accuracy, there was also the matter of primers that would unseat partially out of the case. Through another thread on this forum, I was advised that one possible solution could be to reload "fire formed" brass. Reloading had been a desire of mine for quite some time, so I thought why not give it a shot!

I have a single-stage Hornady Lock-n-Load all in one kit that came with most of what I need to get started, and am now looking at dies. I have heard mention of neck-sizing dies and was wondering what people's thoughts were on these? I have seen a few mixed opinions, and wasn't sure if this might be a more simple option than using a full-length sizing die set to an appropriate height for my longer than standard head spacing?

[Delkal]

You should get the headspace checkek. Sounds like it is excessive and most people will say unsafe. Luckily Arisakas are the strongest actions of all WWII rifles (maybe all bolt actions).

If you are willing to understand the risks (and won't hold me responsible for posting something wrong or stupid on the internet) here is what I do.............

Seat the full length sizing die out so it just bumps the case shoulder. The easiest way to determine this is to get a dry erase marker and blacken the shoulder. Keep seating the die shorter till you see it hitting. Then a small amount more. A neck sizing die will also work but only for a few shots, you will eventually have to full length resize them. If you do use the method I described.

You are in risky territory so learn how to check for case head separation. But as long as a case is fireformed to your chamber (and didn't stretch or crack in the process) you should (famous last words) be OK. Just don't hotrod your reloads. Keep them on the milder side.

[Twoboxer]

Delkal's advice is spot on. While he chooses to FL size with minimum shoulder bump back from the gitgo, I'd likely opt for neck sizing. You may find that your cases don't last long enough to worry about having to FL size at some point.

HOWEVER, you should purchase both neck sizing and FL sizing dies. You may find a need to play with both sooner than expected.

As Delkal said, you will be asking your case to stretch and that extra brass needs to come from somewhere. When it comes from repeated FL resizing and trimming, it eventually will create a groove inside the case just above the base. Here's a good, brief bulletin with photos showing how to check for this "Incipient Case-Head Separation":

http://bulletin.accurateshooter.com/...t-the-problem/

[Gunsnwater]

You should get the headspace checkek. Sounds like it is excessive and most people will say unsafe. Luckily Arisakas are the strongest actions of all WWII rifles (maybe all bolt actions).

If you are willing to understand the risks (and won't hold me responsible for posting something wrong or stupid on the internet) here is what I do.............

Seat the full length sizing die out so it just bumps the case shoulder. The easiest way to determine this is to get a dry erase marker and blacken the shoulder. Keep seating the die shorter till you see it hitting. Then a small amount more. A neck sizing die will also work but only for a few shots, you will eventually have to full length resize them. If you do use the method I described.

You are in risky territory so learn how to check for case head separation. But as long as a case is fireformed to your chamber (and didn't stretch or crack in the process) you should (famous last words) be OK. Just don't hotrod your reloads. Keep them on the milder side.

But see. It would have weakened the case already, in the time span where the primer backed out the front walls gripped the chamber and the unsupported head stretched back. Headspace needs to be corrected to be safe.

[flygrimm]

Just had the same thing with my M1903 Springfield. Got a new barrel installed as the old one had a lot of pitting just ahead of the chamber. Assuming all was well went to the range with 50 reloads and proceeded to blast away. Noticed that some of my primers had backed out. Didn't think much of it as I had a 'new' barrel. Got home and started measuring things. Long story short the gunsmith must have leaned too hard on the reamer as the chamber was WAY too deep. Sent back and he fixed it with another new barrel. I did get a set of headspace gauges and did check his work before going back to the range.

The rounds that were fired in the bad barrel showed 2 different ways of stretching. The first was that the cases stretched about 12 thou. The other was that the primers backed out about the same 12 thou. Was about 50/50. The reloads with IMR 4350 tended to have backed out primers and the ones with AA 2700 mostly stretched. Point is is that if you just neck size your brass you may still have primers backing out.

Get your headspace checked and get it fixed if you can before shooting again.

Stuart

[marstev]

Thank you all for your "friendly" tips and advice. No worries Delkal, if I blow up my rifle, its all me. lol

I have ordered both dies, and as it turns out, the neck sizing die is on backorder until July, so I guess I'll be starting with the full-length sizing die. Have not settled on a bullet or powder yet, but I am leaning towards the Hornady 160 grain Interlock RN with IMR 3031. It is a slower moving bullet, starting at around 2000fps, but I guess I should be more concerned with the pressures, so I got a little more research to do there.

As to my headspacing, I am at a loss on how to check that. There are a few "universal" gizmos out there for measuring, but as far as I can see, there is no actual gauge for the Arisaka due to the lack of engineering data from the old country. The fire-formed cases, for what it's worth, are not really that different than the factory ammo I haven't shot yet. If anything, they are a bit shorter than the Hornady specs in the reloading manual, while I would have expected them to be slightly longer. Case length is measuring around 2.000", while the book says it should be 2.008"? Diameters appear to be slightly enlarged, but straight with no bulging. Aside from the corners being a little rounded, the neck lengths seem to line up. Any idea what kind of tolerances I should be looking for? +/-.005" is a common standard machine tolerance, but this ain't no Bridgeport.

The final concern I have is that the primers on the fired rounds are protruding anywhere up to .015" beyond the breech of the case, where the unfired rounds are around .005"-.008" below the surface? Originally thought this might be a headspacing issue, but not sure since the other dimensions seemed ok.

[Delkal]

The overall length of a case has nothing to do with headspace. After a rifle round is fired the neck lengthens some and you have to trim it occasionally. The books will show a min and max length. Headspace is measured from some point on the shoulder and is difficult to measure without the right gauges.

The canned response to any question like yours is to get the headspace checked.............up to you are a fool for shooting it and will blow up. But I am not convinced you have a headspace issue yet. When ANY rifle round is fired the firing pin rams the case forward. If the headspace is bad this can leave room in the back by the bolt, the case locks in place, expands, and the case gets stretched back till it meets the bolt again. Repeated stretching makes the case thinner an can lead to case head separation. But this can also happen with soft brass and a strong military firing pin spring. The force of the firing pin rams the case into the chamber (like a reloading die) and you create an artificial "headspace"

Also when firing the pressure from the gasses ALWAYS pushed the primer out some. Even with in spec chambers. With a full powered load the case then stretches back (weakening the case slightly) and reseats the primer. If the pressure is really high the primer gets flattened and even cratered. Your primers backing out and not reseating means the case isn't stretching. Likely from a light factory load. On the plus side this means your brass is not getting overworked and thinning.

I would still just neck size or slightly bump the shoulder when reloading. Read everything you can about the signs for a case head separation and also look up how to feel for case thinning with a paperclip. You basically scrape a bent thin piece of metal in the inside of the case. If there is thinning or a crack starting it will catch.

[GeneCC]

Thank you all for your "friendly" tips and advice. No worries Delkal, if I blow up my rifle, its all me. lol

I have ordered both dies, and as it turns out, the neck sizing die is on backorder until July, so I guess I'll be starting with the full-length sizing die. Have not settled on a bullet or powder yet, but I am leaning towards the Hornady 160 grain Interlock RN with IMR 3031. It is a slower moving bullet, starting at around 2000fps, but I guess I should be more concerned with the pressures, so I got a little more research to do there.

As to my headspacing, I am at a loss on how to check that. There are a few "universal" gizmos out there for measuring, but as far as I can see, there is no actual gauge for the Arisaka due to the lack of engineering data from the old country. The fire-formed cases, for what it's worth, are not really that different than the factory ammo I haven't shot yet. If anything, they are a bit shorter than the Hornady specs in the reloading manual, while I would have expected them to be slightly longer. Case length is measuring around 2.000", while the book says it should be 2.008"? Diameters appear to be slightly enlarged, but straight with no bulging. Aside from the corners being a little rounded, the neck lengths seem to line up. Any idea what kind of tolerances I should be looking for? +/-.005" is a common standard machine tolerance, but this ain't no Bridgeport.

The final concern I have is that the primers on the fired rounds are protruding anywhere up to .015" beyond the breech of the case, where the unfired rounds are around .005"-.008" below the surface? Originally thought this might be a headspacing issue, but not sure since the other dimensions seemed ok.

I second the advice on checking headspace. There may not be any headspace gages out there. In which case you might consider "slugging" the chamber, something I'm fixing to do with a World War 2 vintage rifle. I bought a set of crayons for this purpose though I'm told that cerrocast works better than crayons.


I reloaded a 7.7 Arisaka that had a chrome bore. At least most of us thought it was chromed.

I used both 3031 and I believe Win 748 with Sierra 150gr flat base spire points. I would prepare the cases by fireforming 30-06 cases using Unique and corn meal. I then trimmed the necks to fit. Unfortunately I did not bother with neck sizing. I would discard the brass after a few reloads because I noticed the full length resizing really moved the shoulders back.

The 6.5 would work fine with either IMR or ball propellant. I would go with the Winchester 748 or one of the "family" of close equivalents from Hodgdon. Hodgdon has a set of loads for the 6.5 x 50 Japanese, most of them using ball propellant. Ball is a bit more progressive than IMR, has a lower flame temperature but is bit tougher to ignite in cold weather (or so I'm told).

I don't know what sort of propellant the Japanese used in their rifles, though I have seen Arisaka 7.7 rounds brought back from China. I pulled the bullets on some of them. They used a short IMR looking propellant, a stick shape with a hollow core. The diameter looked wider than IMR but the grains were shorter. As to how they were deterred and how they performed, I do not know. I reused the bullets but discarded the remainder. The bullets had long Spitzer profiles with no boattail. Some of the powder had bright orange spots on it, somewhat like photos of Cordite. The powder had an acidic smell. I regret that I did not save any of this ammunition.

You can use a paperclip to find that "gap" which is caused by stretching near the head. You can also form a tool from mild steel or plastic. The goal is to detect a "ring" inside of the case which indicates that the case is thinning at that point.

[flygrimm]

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So after a little research, it looks like the 6.5 Japanese headspaces on the rim like a .303 British, 30-30 Winchester, etc. Headspace should be around 60-64 thousandths. Measuring the actual headspace in a rimmed cartridge is not easy. If you have the set of gauges as long as it closes on the go gauge and not on the no-go then you would be somewhere in between min and max. Another poster at another forum says that commercial 6.5 Jap has undersized rims that could exacerbate the issue.

Here is a possible solution. Somewhere in internet land is a technique for fire forming .303 British, a rifle with generous chambers. You put a small band around the cartridge just ahead of the rim. When you close the bolt the head of the cartridge is forced against the bolt face. When you fire the round, the firing pin will strike the primer but the case will not move forward due to the rubber band being mashed between the rim and the chamber face. The cartridge will fire and move the shoulder forward to meet the chamber. The case will now be a perfect fit in your chamber minus a tiny bit of spring back. When you reload the case just neck size the brass and go from there, no need to use the band after that first firing of that case. When the cases get difficult to chamber just use your full length re-sizer to bump the shoulder back about 2 thousandths. This technique greatly extends the life of the .303 brass. Case necks usually split before the case wears out unless you are using heavy charges. A bit of annealing of the necks every 4th or 5th reload will extend life even more.

Stuart

[pete1955]

You use a small thin rubber o-ring and not a rubber band and make sure you grease the locking lugs, to prevent lug wear.

Below no o-ring and the case stretching to meet the bolt face.



Below using a small rubber o-ring that holds the case against the bolt face. The o-ring when compressed also "centers" the rear of the case and helps the case expand equally. Some people use a rubber band for braces or a childs pony tails, "BUT" the "square" rubber band must not be twisted or it it can hold the rear of the case off center and to one side of the chamber. And with a rubber o-ring you will not have this problem



Thereafter you neck size only and let the case headspace on its shoulder and not the rim.



I fire form my .303 British cases using a rubber o-ring with 100 grain .312 Hornady pistol bullets and reduced loads of SR-4759 or Trail Boss powders.

The 100 grain bullets and reduced loads make the metal butt plate "softer" when fire forming 100 to 200 rounds.