Gun friendly machine shop

[Carriertxv]

Anyone know of a machine shop preferably in S.E. Calgary that has V-anvil micrometers to measure a slug from a 45/70 Springfield trapdoor 3 groove barrel?

[Jayhad]

I would think the guys at Magnum machine, aka Alberta Tactical Rifle, should be able to help you.

[Dean2]

Magnum machine, Rick, are great guys and would help you out, but realistically for what you are trying to measure, land and groove, a set of Mastercraft Digital Calipers, on sale at CT right now for $13 would do the job. About the same as the gas to drive to Rick's in the north end and back.

[Gary K]

fun fact. those calipers, nearly all digital ones, are only accurate to +- .005"

you can step it up to some Mitutoyo digitals for around 200$. that will get you to +- a thou. .001


its frustrating when some of this equipment has 4 decimal places, yet is only accurate to 3.

[Don Andersen]

The cheap stuff is sold as accrurate to 0.000”
The quality measurement calipers are rated to 0.002”

Go figure.

Don

[bat119]

The fourth decimal is a moot point in this case bullets, sizing dies and moulds are sold as .457,.458, .459

Going to a custom mould for 45-70 trapdoor wouldn't gain much. I use Bullet barn's 405 grain .459 with 53 grs. + wonder wad (thrown) of 777 replicates the original carbine round. close enough for me.

[Dean2]

Mitutoyo 500-196-30 Cost $135
6" Digimatic Calipers No Output 6"/150mm

Product Highlights
Material: Stainless Steel
Resolution: 0.0005"/0.01mm
Range: 0 to 6"/0 to 150mm
Jaw Depth: 1.57"
Accuracy: +/-0.001"

Mitutoyo 510-131 Cost $800
Indicating Micrometer 0-1 in

Range 0-1in
Indicating Range 0-.0023in
Retractable anvil with indicator for threewire measurements of pitch diameter of precision screws, and parallelism measurements
IP protection level: 54
Supplied in fitted plastic case
Spindle feed error: 3¬m/ .00012"
Dial indication accuracy: 1¬m / .00004"
Dispersion of indication: 0.4¬m/ .00002"
Graduation: 0.001mm or .0001"
Dial reading: 0.001mm or .00005"
Flatness: 0.3¬m/ .000012"

I have checked a few Mastercraft, I use them in places I won't take my good ones. They aren't nearly as precise or well built as the expensive ones but with the right touch they are fairly accurate. I have compared their readings, against Mitutoyo and Starret Calipers and have never found one that was off the reading by more than .0008 of what the expensive one reads. Also, my Verniers are pre-calibrated and read the same to .0005 as the micrometers that read to .00005. All in, for $13 buck, and considering what is being measured, I still say the cheapies will get the job done for the average reloader.

[32-40win]

You'll see more difference in the size of a cast bullet from the differences in the tool the mould was cut with, and in the alloys you use, than what you can measure accurately with the caliper. And they are close enough for our purposes. Really notice it when you breech seat a bullet, or on the effort to seat it in a case.

[Dean2]

Originally Posted by 32-40win

You'll see more difference in the size of a cast bullet from the differences in the tool the mould was cut with, and in the alloys you use, than what you can measure accurately with the caliper. And they are close enough for our purposes. Really notice it when you breech seat a bullet, or on the effort to seat it in a case.

Are you saying you can feel .001 bullet diameter difference in a cast bullet when you are seating it in a case. IF you can you got a lot better feel than I do. Now when chambering a loaded cartridge in a rifle, I can feel the difference in a case that is .001 over the chamber size, but I can't feel the difference between one .0005 vs .0015 under chamber size.

[32-40win]

You can get up to .002 difference in changing alloys. Not 100% positive in my mind as to absolutely feeling a .0005 difference in seating in a case, as it isn't fresh in my mind, haven't done that for a while, but I do remember noticing differences in doing the same batch of cartridges, with two and three alloys. You do notice it when breech seating.

[Carriertxv]

I have calipers and micrometers. The problem is the 3 groove barrel. It’s about impossible to get a accurate read on an odd number compared to an even one.
I will give ATR a call and see what they say.
Thanks to all for information.

[Carriertxv]

Just an update. I slugged the barrel and took slugs to Alberta Tactical. Shawn and Gabriel were awesome and I’m very happy with the results. My 136 year old trapdoor barrel has almost zero wear.
Thanks Jayhad and Dean2.