Correct Reamer for 8mm from 30-06

[RogerDat]

I think I would get better results to making 8mm by using a hand reamer when cutting down and reforming 30-06 military brass.

I don't have any issues with chambering after reforming but I think the neck is thicker and swaging down the lead bullet a bit. I looked at 8mm reamers and they would still seem a bit tight to me at .31 for a .324 lead bullet with PC.

If I first size outside of case only (Lyman 8mm cut off die) ream to .31 with an 8mm ream, then run through a sizing & depriming die should I expect the neck size to be improved by removing excess metal before sizing inside and outside of neck? I think the Lyman cut-off 8mm die should size outside causing any surplus wall thickness to be pushed in where it can be reamed. Then second run with regular sizing die that does inside and outside of neck will give me a proper sized neck.

Just want to make sure I order an appropriate ream and apply it at the correct stage of the process. I use 30-06 military brass without a caliber stamped on the head that would be inappropriate to the completed conversion to 8mm. Don't have anything to use to remove stamping on the head so I make it so the head isn't a "false" caliber label. The few I made so far "work" but I see some loss of accuracy with them, I suspected swaging the bullet down under what an old milsupr Mauser bore needs.

[Rfeustel]

Have you considered the L E Wilson inside neck reamer for 8mm (for fired cases)?

[TurnipEaterDown]

I have reformed a fair bit of 30-06 brass to 8x57, and other brass for other wildcat cartridges as well.
Couple things to look out for, especially when moving the neck or shoulder junctions around:
Different makers taper the cartridge brass differently in drawing. Necks should always be checked for thickness, and for the formation of a "doughnut" at the Bottom of the neck.
General neck thickness is easy, the doughnut may slip by unseen and cause issues. On a bigger neck, like an 8mm, I can usually get by w/ my dial calipers for measurements of inside neck diameter, and of course outside is always easy. For inside, Just remember to get several measurements at different distance down inside the neck all the way from mouth to shoulder junction. If you are careful you should detect a doughnut if you get one.
For my 8x57s, the military chambers are so loose I don't have a chambering problem no matter what I do. The issue is more in the sizing, so, what I do is:
Trim the 06 brass to 8x57 length, chamfer, lube with imperial size die wax outside & inside neck, run in 8x57 die, outside turn neck to uniform thickness using the mouth opening diameter as the target size (i.e. turn the thickened neck base walls formed by old shoulder, should they exist w/ whatever brass I used), clean the inside of the neck w/ alcohol on a q-tip or Birchwood Casey gun scrubber, good to go.
Doing this I have had cast in these cases shoot just as good as jacketed in RP 8x57 cases, except for a rare load. Usually ~1.5-2.0" 5 shots at 100 yd, 3" for 20 shots.
What must be done really does depend on 06 brass make used.

I am confused about the headstamp comment. You can't remove it w/o thinning the rim, and that is a very bad idea on a number of fronts.
Reforming cases this way always leaves you w/ incorrect headstamps. You just have to be aware and check the labeling in your box/case.
BTW: Pretty much every military rifle I saw never had a chamber mark unless applied by an importer.

[MostlyLeverGuns]

I would suggest as last step before bullet seating, use a properly sized 'M' die type neck expander. Expanding the neck using a .321-.322-.323 neck expander should remove any issues with a 'doughnut' or other case neck problems. Unless your case necks actually have interference from the chamber, reaming may not gain much benefit. Case 'springback' or using a standard pull-through expander ball may not be expanding the case neck enough to allow bullet seating without bullet sizing or damage. I have made many 8x57 out of US military 30-06 and have not run into a chambering problem with the sized and cut-off brass. You might check your fit using a Sharpie to color the case neck, with and without a bullet seated before worry about neck reaming. As long as the case neck is not TIGHT in the chamber, a thicker, closely fitted neck usually gives better accuracy. If you are concerned about the cases being 'mixed up' for 30-06 and chambered in the wrong rifle, use a a Sharpie to color the head red or black or start with 270 or 280 brass so improper chambering is much more difficult.

[Mk42gunner]

I don't have any issues with chambering after reforming but I think the neck is thicker and swaging down the lead bullet a bit.

Bold added by me.

I will suggest getting a tubing or case mouth micrometer. They aren't all that expensive, and take the guess work out of case measurements.

I have never inside reamed a case neck, but as I understand the process, you want to do it with the case supported by a forming die.

Robert

[bdicki]

8mm-06 checking in.

[Larry Gibson]

In days past, when I was forming 8x57 cases from 06 milsurp cases I found the necks certainly were uneven in thickness mostly back toward the shoulder. Since i was mostly NS the cases anyway I found outside neck turning to be a simple solution. I turned the necks so mostly the thicker part at the rears of the neck was turned off. That gave nice even necks that were concentric enough for the mostly cast bullet loads I was shooting. If I was to form cases again [I have sufficient commercial cases now] I would clean the necks up outside turning them with the Forster turning tool that fits on a Forster case length tool.

[RogerDat]

I know some folks run their modified cases through a lathe to mark through or remove the now incorrect head stamp. I just used military brass since it has no caliber on it the case doesn't tell a lie.

I use the NOE button sizers to perform the function of the Lyman M dies, I'm going to double check if I have one for 8mm. I try to have them for each caliber I reload but I can't swear I have them for 8mm. It was an early round for me to reload, pre-dates the NOE buttons being available.

Good to know that the chambering of the case is expected in an old milsurp with less than tight dimensions. Also the suggestion that if I am going to ream I do it with the case supported sounds good.

That "L E Wilson inside neck reamer for 8mm" sounds like it may be exactly what is needed. Little more expensive than a regular reamer but it looks to be designed to be used by hand and is made for 8mm. Trying to sort of work through how that would work if used on a fired case before it is sized. It seems to me it would just remove any surplus metal and leave a fire formed case ready to load after neck sizing. Will be looking for YouTube video or written reviews or guides on use of that reamer.

Neck turning is a bit spendy since I don't have the basic equipment already.

There was a time when 8mm was pretty hard to come by so getting the Lyman form die for conversion of 30-06 brass made sense. Now thinking maybe I should go ahead and do the conversions on the brass I had sitting around waiting to convert, even though since I bought the conversion die I did pick up a bunch of 8mm brass. I set aside a stack of 30-06 brass to convert. Makes a decent winter project.

[skeettx]

I use an RCBS trim die, then Forster inside neck reamer to final length and ream
and then RCBS full length sizer, then Lyman M die,

https://www.huntingtons.com/store/pr...roductid=19005

Works GREAT

Mike

[RogerDat]

I use an RCBS trim die, then Forster inside neck reamer to final length and ream
and then RCBS full length sizer, then Lyman M die,

https://www.huntingtons.com/store/pr...roductid=19005

Works GREAT

Mike

Thanks for the link. Looks like I may need to consider what to buy before I buy a ream that won't be appropriate to the final solution. Wilson hand reamer would be $34 but wouldn't work with the Forster case trimmer. Becomes a question of spending the approx. $150 for a really nice set up or the $34 to just get a Wilson hand reamer. I use Lee trim dies to trim brass so switching to the Forster is a bigger financial decision than just buying the correct size ream. New device leads to new accessories etc. On the other hand it may open up new opportunities too.

I'm guessing that folks who anneal the neck do so post forming to 8mm to avoid having brass be too soft and not form properly. As well as annealing out the stress from the forming of a new neck further down the case.

[racepres]

I must be Not Careful enough... form lots of 8mm from -06, never reamed nor turned any... Dumb Luck???
If a cast, gas checked, Boolit drops into a fired case... I figure I'm good to go... Why Loosen anything...
Flame On....

[RogerDat]

I must be Not Careful enough... form lots of 8mm from -06, never reamed nor turned any... Dumb Luck???
If a cast, gas checked, Boolit drops into a fired case... I figure I'm good to go... Why Loosen anything...
Flame On....

I didn't either and they worked. I just was thinking they might be made to work better Figured to pursue options before I loaded up 50 cases.

[country gent]

If your going to hand ream in a die ( this is best as it supports the neck keeping it from expanding away from the reamer ) For a .324 dia bullet then a .322 dia reamer would leave .002 neck tension. when neck reaming the bullet dia minus the desired neck tension = reamer dia. Also check the wall thickness of the case to insure this dosnt thin it to much. Some also subtract .0005 from this for spring back

Normally necking up thins the neck but if your pushing the shoulder back and it is becoming neck then you may have a thick ring there to deal with. You really need to watch this when reforming brass as you can get a round that chambers with no room for expansion to release the bullet causing high pressures.

Reaming as above makes your stanndard sizing die almost a bushing die. Those cases wont need an expander ball since the case is reamed to bullet dia in the die.

[S.B.]

Reamer? I simply removed expander plug and sized with a 8mm die then trimmed brass to proper length ran them through 8mm die again with expander plug installed then annealed?
Steve