I bought a .450 NE reamer from Pacific Tool and Gauge (PTG) and unknowingly rented a reamer from 4D Reamer Rentals, which apparently was made by PTG. So they are/were of the same dimensions.

Both reamers had base diameters of .542 inches. The guy at PTG was quoting me the C.I.P. standard as .542 inches. Either that or the mm to inch calculator conversion is screwy.

The problem is both the Hornady and Jamison cases have base diameters of .543 to .544 inches. And the Barnes (Cartridges of the World) shows a case base diameter of .545 in.

Then the reamer has to be a bit bigger than that?

So am I screwed up, C.I.P. screwed up again (I can't find the drawing, as yet), or what?

Any clarification?

Thanks.

Bill,

I have no experience with your particular caliber.

But, in both our Hyem 600 NE and our own built 700 NE, we have to turn the rims down to fit the rifles.

Commercial brass will not fit.

I have no idea why this is the case.

Ever contemplated that the people who make the reamers might be the one's at fault, not CIP ?

Might be worth asking Hornady why the H Brass is spec'd as it is. It might provide an answer.

.

quote:

Originally posted by 500N:
Ever contemplated that the people who make the reamers might be the one's at fault, not CIP ?

Might be worth asking Hornady why the H Brass is spec'd as it is. It might provide an answer.

.

Yeah, but they claim otherwise! I just found the C.I.P. drawing and yes indeed the reamer is screwed up. The guy at PTG was supposedly looking at the drawing and saying it was .542 inches. Well, that seems suspect, eh?

The C.I.P. drawing dimension for the base is 13.84 mm max, which is .545 rounded off, so yeah the reamer is screwy.

The minimum chamber dimension is given as 13.87 mm, or .546 inches. So the reamer is way undersized.

Should have found the drawing before asking this/posting the question, but too late now.

Thanks.

quote:

Originally posted by Will:
Yeah, but they claim otherwise!

Which is why drawings are available as you have since found out.

Of all the cartridges to be wrong, the 450NE is not one I would pick
considering.

.

There is a bit of a mathematical problem in the calculations from MM to IN and vis versa, you have to take it out to at least 6 decimal places to get it close and even then there is, most likely, a difference and most reamers are cut within 0.001" plus or minus of the tolerance anyway(PT&G states that on their drawings explicitly or at least on all the reamer drawings I've received from them), there are tolerances issues as far as dimensions are concerned in the machinery...how each person takes measurements, a minimum/maximum tolerance that is indicated in the fine print on ALL mechanical/engineering drawings for ALL the machinery involved in grinding...and so on.

It doesn't seem "screwy" to me as far as your indicated measurements are concerned...just not well understood by you...no diss or flame intended...nothing is perfect in this world and you're not the only one that has questioned this issue on some forum.

Hornaday and Jamison also has their own set of tolerances for their brass...but it is better to measure an actual case...most of the new brass I ever worked with, no matter WHO the maker, was undersized as far as the chambers were concerned.

Besides most factory ammo is sized to fit ALL chambers so it is "undersized" at the base to begin with. Measure some Hornady factory 450 NE ammo and see what base size it has.

So combining all the variations and you come up with the numbers...and the variation, which is usually not a problem in factory components, only when a "different" caliber in this case is considered.

In your case it sounds like the horse got in front of the cart...by the way PT&G makes reamers and other cutting tools for a WHOLE lot of other places...most of the reamers from Reamer Rentals are done by PT&G or at least all the ones I've used, as they are in the same state and just "down the road" from each other and the reamers have always been very high quality and usually spot on as far as the drawings they used are concerned.

I have one question tho'...How did you "unknowingly" rent a reamer from 4D?? Seems to me either you did or you didn't...I've never "unknowingly" rented any reamers from anyone...or am I reading that wrong.

And you seem to have the min/max dimensions reversed in your post...am I reading that right?

All my data give O.545" as the base dia for the 450 NE...so the PT&G reamer might be considered slightly undersized at 0.542", but as this cartridge is usually used in a double rifle that would be fine for me as 0.003" certainly isn't excessive as far as resizing is concerned and at factory pressure levels might not even move the base dimensions...only firing will tell.

If you haven't cut any chamber yet...I would pick the brand of brass you want to use and maybe a couple of other brands and send them and the reamer back to PT&G and indicate the problem with the dimensions...Dave will correct any problems and get you what you need, THEN fireform 3 cases in the chamber and send then to the die maker of your choice for the dies.

At least that is what I would do if the brass seems to be the problem area...eliminate the problem before it becomes a problem.

Alternatively if only one brand of brass is causing the ruckus you can alwasy turn down the rims a bit if that is the problem area and solve that problem easy enough.

I'm not trying to be simplistic here, but I don't really see any insurmountable problem or cause for road rash as I would rather have a slightly "undersized" chamber...0.001 to 0.003" depending on how you look at it...than have an "oversized" chamber by the same amounts...and remember your talking about the thickness of a piece of Postit scratch paper. That amount is a problem in a high pressure hydraulic pump, but not in a rifle chamber...

I have NEVER found a reamer by ANY one of the reamer makers I've used that wasn't plus or minus a bit different than SAAMI or CIP specs...you just CAN'T, for all intents and purposes, grind a reamer perfectly as there are tolerances in all phases of the process.

Hope you solve your problem.

Luck

Foobar

Lucky he's not trying to fit it into an Old English DR, the variations in chambers of English guns is a heap more than 0.0003.

.

CIP isn't to blame .. persons unable to perform metric to inch conversions are to blame

I think the reamers were cut to the wrong dimensions. Not sure how else to explain it.

Thanks for the comments.

.542 is cartridge base, right, not chamber?...

+.003 in most dimensions is what most reamers are drawn...

wanna get pissed? mic the casehead on new 30-06 brass.. it is nothing like close to .473/12mm

quote:

.542 is cartridge base, right, not chamber?...

Both the Hornady and Jamison case bases are the same, slightly out of round, .543 to .544. So a .542 reamer won't allow the cases to drop into the chamber.

I am not a chambering wizard and didn't think about it. I should have measured the reamer in the first place.

quote:

Originally posted by Will:
I think the reamers were cut to the wrong dimensions. Not sure how else to explain it.

Thanks for the comments.

Ask PTG to look at the CIP drawings and explain what size their reamer is supposed to be.
Remember that the NE is a British design so CIP could have taken their standard from incorrect drawing.

Under those circumstances I would send the reamer back to PT&G or at least call Dave and find out what going on...they could have made a mistake or could have ground the reamer to THEIR minimum dimensions.

Then let us know the results.

I hear that 500N. Every gunsmith had their own ideas on how to do things and they wouldn't budge.

I was futzing with my 9.3x62 today Will, all my data says the base should be 0.476", but the fired cases are 0.474"(Lothar Walther prefit M98 barrel), the sized cases are 0.472" and the 35 Whelen brass I'm using are 0.467"-0.469" out of the package...hows that for the start of a hoohaa.

The only times I ever got real twitchy is with my benchrest guns and brass...a few tenths is the difference from getting the tin pot and being so far down the list it isn't worth looking.

I don't think I ever came across a minimum cut factory chamber, but most of the reamers I have rented or bought were minimums or sometimes slightly smaller...all it takes is a few regrinds to get too small. But that's the beauty of a good die maker...he can make the dies to fit the chamber dimensions.

On my last wildcat, my 510 Makatak, I had the reamer made by PT&G, then I cut the chamber, THEN I fire formed 3 cases and sent the reamer AND the fireformed case to CH4D to have the dies made, and requested the sizer be 0.001" to 0.0015" smaller at the base than chamber size INCLUDING springback and 0.002" shoulder setback. They came back perfect even though it took 8 months.

Your definitely right Jeffe, brass is so variable I don't bother miking until after the first firing. And talk about variations in case capacity...there is 6 gr H20 difference in case capacity between the RWS 9.3x62 brass and the Win 35 Whelen.

Lots of variation in all the areas in this sport.

Luck

Could it be a roughing reamer instead of a finish reamer?

It is too small in base diameter for a finish reamer.

It is too big in base diameter for a reloading die reamer.

Note that the "450 Nitro Express 3.25-Inch Thin Rim" reamer will clean up a .458 Lott or .458 WinMag chamber, like in a Ruger No.1.

Is "Pondoro Will" converting an 0/U-single-selective-trigger-automatic-safety-ejector-458WinMag double rifle to 450 NE, or what?

Maybe a sizer reamer...??...0.542" would be just about right to size a 0.545" fired case back to drop-in configuration.

A roughing reamer should be a few thou over 0.545"...like 0.548" plus/minus a bit...Yes?

But all this conjecture isn't worth much as the only way to get to the facts is talk to Dave at PT&G...maybe the CNC reamer machine had lost calibration, or the person who did the reamer program lost calibration...who knows?

Or...alternatively, mike a standard sizer die if anyone has one. This would certainly help somewhat.

I'm sure all the measurement conversions are done by a sub program within the drawing program within the CNC machine program...I'm certain PT&G is well beyond the "pencil and paper" calculation arena. Conversion programs are scattered all over the internet...I have at least 6 links that cover ALL kinds of conversions, plus all my big and little calculators have built in conversion...just call up the program, plug in the numbers and hit the equal sign. Of course I run it a couple of times and have a rough guestimate in mind just for a check.

Where are all the real experts when you want them?

Luck

Luck

Look at page 106 of the CIP pdf file for the 450 NE.

http://www.intermin.fi/intermi...A/$file/TABIIcal.pdf

fobar -- otherway ,, rougher should be under sized, so the finisher works

Jeeze....where was my mind??? Total brain phart. Thinking one way and fingers doing something else.

You're definitely right. See...the experts are well and on post. Thanks.

Mike...I tried the URL...couldn't get it to open. Could you re-up it or post the data...for some reason this conundrum is keeping me up at night. Thanks

Luck

foobar .. it a big pdf on the link .. right click it, select save as, and watchit download

and i've made MUCH bigger brain farts that swapping those things around

Thanks...Jeeze, no wonder it was not downloading...and I'm on dial up sooo......

I have a slight problem with math...similar to dyslexia only with numbers. I get caught now and then no matter how many times I proof read. Made life he** with the higher levels of math, and even worse doing fabricating. You'd laugh watching me do engine bores or lathe turnings when the mind starts going south. Hahahahahahabahumbug

HO, MAN...VERY NICE DATA DUMP...THANKS MIKE.

lUCK

No Problem Foobar. It's been handy for me on occasion too.