OT - Neck Reaming vs. Outside Turning

[Rimfire McNutjob]

I've got some 450 Alaskan brass that was likely formed from 50-110 stock. It's from Quality Cartridige, so I'm speculating here. In any case, the necks are too think and I have turned some of them to remove about 0.0015" from their thickness using a Forster hand tool.

I've also noticed that Wilson, Forster, and others make inside reamers in 0.458". Most of the other companies seem to make inside reamers up to 0.375" but no larger.

Is there a specific reason to inside ream instead of outside turning? Is inside reaming used on unfired cases where outside turning is used on fired cases? Does one method promote more concentricity and is therefore favored by competitive shooters?

Just trying to learn. It seems like something I should understand if I'm going to handload a wildcat.

[Sixgun]

Mr. McNutjob, (I like that name! )
There are several reasons of inside vs. outside turning. When forming brass from a large caliber down to a small one, the brass gets thicker on the inside, down towards the shoulder and makes inserting the bullet a little hard, hard chambering, which all leads to erratic pressures. Cocentricity is important as most guys who form cases are usually using a very accurate rifle. Another reason is like me, whose Foster outside neck turner only works on calibers up to .375. I have had Foster make me special order inside reamers of the 40-82 and 40-65. These enable me to use a .408 bullet in a chamber that normally would not take a .408 bullet. The same can be done for guys who need to use a fatter bullet in the often small chambered 38-55's.

Inside neck reaming is done after sizing and neck expanding. If it was not done this way, you would way take too much out of the neck, maybe even cutting the neck off.

As for preference, I think its a matter of choice. Outside neck turning is certainly a lot cheaper as you only need the one tool where with inside reaming, you would need a special reamer for every caliber, and sometimes, for every gun, even if the calibers are the same. The idea with outside turning is to get the neck perfect so it aligns with the chamber and has the same amount of "release" of each bullet when it is fired--that amounts to more "even" pressures--therefore possible better accuracy. Its like "paying attention to detail" which I am usually a failure at

There's a lot more but these are the basics--------------------------Sixgun

[Rimfire McNutjob]

Anyone sporting a 71 bolt-peep avatar must be an expert in all things gun related as clearly he has mastered "taste" in firearms.

Thanks for the info. I will stick to outside turning with my little Forster tool. It's not a high volume operation for me anyway. I just didn't understand why one would go one way versus the other.

[geobru]

I had a discussion about this with a machinist just last Friday. Like Sixgun, I have a 40-82 that requires a .410 bullet and a chamber designed for a .406 bullet. I've been turning the outside of my cases to get the brass down to the point where it will chamber the larger bullets. I use a Lee three jaw chuck in a drill and a flat file to remove the excess brass.

My friend suggested that I ream the inside of the case because by messing with the outside of the case, I am changing the uniformity of the case that is created when it is full length sized. Logically, this point of view makes sense to me. With my eyes though, and with this particular gun, I don't think it will make much difference in accuracy, but if you are loading a gun for extreme accuracy, I think his point of view has some merit. As Sixgun said, "attention to detail".

For now, I will continue to take the excess brass off the outside. I don't have a Forster tool, and the difference in cost when I looked at this was around $15 for the Lee tool versus $80 - $100 for the Forster setup.

[Tycer]

I feel better using an inside turner when using a short-necked cartridge or a bullet that will extend to, or past, the neck for the same reason mentioned above - I worry that outside turning cuts too much off where the neck meets the shoulder.

[KirkD]

I formed some 40-82 brass from Starline 45-90 brass. After forming, I stuck the case in a drill chuck and then, while rotating the case at medium speed so that the flat file did not bounce, I reduced the outside diameter of the case until it would chamber .410 bullets. I measured the neck thickness before and after turning for uniformity and found that the uniformity was the same before and after (within 1 thou). I don't think outside neck filing would work if you had to take it right down to the shoulder, although you may find that you don't have to if the chamber shoulder is forward of the case shoulder. Outside filing works best with more or less straight-walled cases or cases with a longer neck that the bullet seating depth.

[Ben_Rumson]

No matter how you get there, the proper bullet fit to the barrel will give the biggest accuracy gain...Outside neck turning with a proper fitting mandrel in the case neck will remove brass from the thicker side of a case if the brass is not a uniform thickness all the way round.. and is supposed to therefore make for a more concentric case.. reaming will thin the neck but may not leave uniform case neck thickness depending on how much thicker the brass is on one side of the case to the other side.. You could wind up with a bullet sitting off center a little to the bore ....off center a tad to the bore means plenty to guys with tight chambered target and Varmint rifles, but for walking around hunting rifles?

[Wrangler John]

I agree with Sixgun.

When forming to a smaller caliber, or moving a neck into the shoulder area you need to inside ream. However this should be done with a neck ream die and reamer especially made for the purpose. Inside reaming removes the excess brass from the interior, decreasing the possibility of creating a "donut" inside the case at the shoulder junction or base of the neck. Also, by holding the case inside the die (which is a full length sizing die), the reamer is cutting axially to the case body and will perform the same job as an outside neck turner. Looking inside a die reamed neck you can see where thicker brass has been removed, and the micrometer indicates a uniform thickness. The reamers held in a case trimmer are going to follow whatever error in brass thickness exists and can cut eccentric necks. RCBS makes neck reaming dies for most cases, but you pay for them.

Neck turning is good for uniforming neck thickness and matching a chamber throat, but leaves a slight step at the shoulder junction. It's quick and easy.

Getting a good match between the reamed case and rifle chamber is where things can go awry, which is why some dies are matched to the chamber - an added expense. For the lever gun in large caliber cases I'd just use a neck ream die after forming, or to uniform different lots and brands of cases. That way the bullet will be seated concentrically and with uniform tension.

[AJMD429]

Lee used to make a "Target Loader" kit which included a micrometer seating die and an inside neck reamer, along with a fancier version of their famous "no-press-needed" kit. About $28 if I recall, and it made excellent reloads. Wish they still made them, for low-volume reloading it was great.

[revolverjunkie]

hmm all of that doe make sense but if the neck is oblong to begin ith and you size the neck wouldnt the inside of the neck be unifom case to case? the you cut the case necks to remove the extra brass making the neck round inside and out.
or am i just crazy?