Brass prep and sizing for the auto loader.

[nf1e]

Informational only.

The combination of FL dies and brass spring back in the area of the cartridge web can be detrimental to function when hand- loading. Difficulties chambering and in extraction both have been realized. Photos below show fairly good representation of this using a Sheridan cartridge guage to indicate correct and incorrect sizing. A properly sized cartridge should just drop in the guage and drop back out when the guage is inverted. The use of one of these guages for each caliber loaded can save a lot of grief encountered with poorly sized ammo. If your ammo fails with this check, chances are it will fail in your rifle.
The use of a small base die when sizing tends to allow for this spring back and still keep the casing within usable SAMMI measurements and is highly recommended.

First photo is FL sized and a no/go.



Second photo is SB sized and a GO.

[bruce]

The sizing requirement for handloads varies with the rifle(s) being used. For a modern commercial rifle w/ a chamber perhaps cut on the tight side of the SAAMI standard, a SB die especially in an semi-auto is useful. Loading for typical surplus military rifles, especial when the rifle is a semi-auto, a SB die is just about never required. With some calibers such as the .303 British, chambers are so large that a handloader is wise to size the brass to that large chamber simply to afford at least a few reloads for the cases before the brass fails. Sincerely. bruce.

[nf1e]

The main reason for this informational thread is to aleviate some confusion that exists when modern barrels with tight SAMMI chamber have been installed on M14 type rifles. A few have complained that" I have been using this same loading scheme for years and it worked in all my rifles". Another thing that has come up is " I use a Wilson headspace guage and all my ammo passes". Some re- loaders are not aware that the Wilson guage only checks headspace and not whether the cartridge will fit in a SAMMI cut chamber.
Having experienced the same on some of my own rifles , it seemed a good idea to share the information and hopefully save others the pain of having to pull down loads and resize using SB dies as I have been doing for the last week or so for one of my precision rifles. This should eliminate the " my bolt rifle is really hard to chamber with hand loads , but commercial works fine". Spring back needs to be paid attention to.

[bruce]

Beg you pardon. Sincerely. bruce.

[nf1e]

Beg you pardon. Sincerely. bruce.

No need. All input is appreciated. Totally agree that every rifle is different.

Art

[Sunray]

The use of one of these guages is 100% unnecessary if the FL die is set up correctly. How do you think this was done before there was such a thing?
What the "cartridge web" does or does not do makes no difference anyway. That's the extractor groove and doesn't get resized by any die.
However, by far, most rifles that prefer/require an SB die are AR-15's, not M-14 style rifles. If the chamber is cut to the minimum SAAMI spec, which is highly unlikely with standard reamers, it will still not require SB dies. A small base die sizes a few thou more than a regular FL die. Usually no more than 5 thou or so.
What you think is a Wilson headspace gauge is not a headspace gauge. It's a case gauge. Cartridges do not have headspace. Wilson doesn't call their case gauges headspace gauges either.

[togor]

I think we can keep this civil and avoid nitpicking. The point is that some chambers cut on the tight side benefit from small base dies. Always good to get that message refreshed out there. Thank you, nf1e.

[nf1e]

I think we can keep this civil and avoid nitpicking. The point is that some chambers cut on the tight side benefit from small base dies. Always good to get that message refreshed out there. Thank you, nf1e.

Thanks you Sir. Rgr and the nitpicking.
I have no intention of arguing with anyone. The thread was for information only.
We can agree to disagree. But I am always right. Well, not always, I was wrong once. Humor.
Keep a cool tool.
And enjoy the hobby.

[nf1e]

The use of one of these guages is 100% unnecessary if the FL die is set up correctly. How do you think this was done before there was such a thing?
What the "cartridge web" does or does not do makes no difference anyway. That's the extractor groove and doesn't get resized by any die.
However, by far, most rifles that prefer/require an SB die are AR-15's, not M-14 style rifles. If the chamber is cut to the minimum SAAMI spec, which is highly unlikely with standard reamers, it will still not require SB dies. A small base die sizes a few thou more than a regular FL die. Usually no more than 5 thou or so.
What you think is a Wilson headspace gauge is not a headspace gauge. It's a case gauge. Cartridges do not have headspace. Wilson doesn't call their case gauges headspace gauges either.

I would like to thank our learned member from the North country for your participation in my thread and I will be happy to comment on your post.

1. Whether or not a FL die is set up correctly, there are times when more compression of the cartridge base is necessary to overcome spring back when the die is withdrawn.

2. Before this type of guage became readily available, we used to chamber a piece of barrel stock with the same reamer we used to to chamber the barrel being worked on. Been doing this for over 50 years so it ain't rocket science.

3. The cartridge web, of which I speak , extends up the base of the casing for some distance above the extractor grove and is where the base is comprised of the most material.

4. The majority of the custom barrels that I have been installing, on M14 type rifles for the last few years, indeed have tight match chambers, meaning diameter of the chamber is close to SAMMI .308 min., and generally require SB sizing be incorporated in the brass preparation.

5. The Wilson guages, in my shop, are used as a quick reference of cartridge headspace base to shoulder and overall casing length. The diameter of these is intentionally excessive for easy and quick measurements of length and not intended for checking diameter.

The split Sheridan cartridge guage is one of the most easily viewed methods of determining whether or not re-loaded ammunition will comfortably feed and extract from a rifle chamber. Plain and simple, they perform as advertised.

This is a 10 round test group fired 3 days ago, at 100 yards, with one of my M14 type rifles in it's final stage of completion. Just for reference.

[Tuna]

nf1e. So your were wrong once? Yup.......you said.....I DO. But since then you have been wrong ever since!!!!! lol

[nf1e]

nf1e. So your were wrong once? Yup.......you said.....I DO. But since then you have been wrong ever since!!!!! lol

As long as we continue to make our voyage to Hawaii once a year, I am allowed to be right upon occasion.

[Allen]

So your were wrong once?

Maybe not.

[PWC]

I don't know, but it looks like the 2nd pic swhows the cartridge below the rim, not flush. Excess headspace?Presentation3.jpg

[nf1e]

Good eye PWC. I like to keep my brass short for use in my precision rifles and load the projectile out to a couple of thou from the lands. I have found , at least for me, I am able to get the lowest SD on the chrono this way.

[barretcreek]

Fulton Armory has a section on reloading for autoloaders on their site. Glen Zediker also has a chapter on loading in one of his books. Actually, I am behind the curve here. http://zediker.com/ has his books and there are a couple on ammo for the gas guns. Both sources stress brass prep as the key to a happy rifle.