Conversions

[catman]

Has anyone ever seen a conversion chart from mm to caliber? If so, please post it.

Thanks,
Trav

[Keith_Hixson]

Not sure (My memory isn't what it use to be) but I believe Remington Arms has one on their site.

Keith

[82Rigger]

..can't find a chart for ya at Remington or elsewhere on the net.

Are there any particular metric cartridges you have in mind?

To convert:

millimeters X .03937 = inches (This won't be exact)

Some of the more common ones:

RIFLE

5.56 mm = .223 Remington

6mm Remington = .243

6.5mm = .264

7mm = .284

7.62mm = .30 caliber

8mm = .323


PISTOL

7.62mm = .30

7.65mm = .32

9mm = .354 inches

10mm = .40 cal

11.5mm = .45 cal.


Hope this helps.

[catman]

Steve...that helps a lot, thanks for the effort!

Trav

[Doc.2/47]

catman-

Noted from the other thread that you own a 7.65 Argentine(AKA 7.65 Mauser,AKA 7.65 x 53 Mauser).Thought I'd pass along the following info. taken from the Sierra Reloading Manual in case you're looking for info. on that cartridge:

Bullet dia.=.311 (same dia. as the .303 British and the 7.7mm Arisaka).

You could save a bunch of ammo money and likely improve ammo quality by handloading..30-'06 brass can be run through the 7.65 sizeing die then trimmed back to 2.11" to give you new cases.

Listed max. handloads:
150 Gr. .311 Spitzer=2700 FPS
180 Gr. .311 Spitzer=2500 FPS
____________________________

Might wanna keep in mind that the "stated cal." of a given cartridge and the actual bullet dia. that cart. is designed to use may be very different especially as applied to handgun bullet dia.s.

.38 Spec. uses a .357 dia. bullet
.38 Super,380 Auto,and 9mm all use .355 dia. bullets
.44 Spec.,.44Mag. use .4295 dia. bullets as does the .444 Marlin
.45 ACP,.45 Long Colt,etc. use .4515 dia. bullets while .45-70 uses a .458 dia. bullet.

The .218 Bee,.219 Donaldson Wasp,.219 Zipper,.222 Rem.,.222 Rem. Mag..223 Rem. all use .224 dia. bullets.Go figure.

Just goes to show that what you see(in the cart. name)ain't necessarily what you get(as far as bullet dia.).

[David]

caliber millimeters c.f.== 0.254


Example of the Beretta 92FS CO2 pistol.


4.5MM = (.177 caliber)

.177 x 0.254 = .044958 = 4.49MM or 4.5 MM


Here is a great conversion calculator to take the headspace out of the calculations.

http://www.chemie.fu-berlin.de/chemistry/general/units_en.html

[catman]

Thanks guys!

Trav

[colmurph]

'Nother "cute" one. .38 Colt has a .357 dia. bullet but the older .38 Long Colt had a bullet of .375 dia. Colt .36 cal. percussion used a ball or conical bullet of .375 dia. which can be used in the .38 long colt if you have an old mold.

[82Rigger]

...started handloading in the early sixties all of the "22 caliber" centerfire cartridges used .224 diameter bullets...except one, that used a .223 diameter bullet. Trying to remember which cartridge that was.

Doc...

Many times I've wished some company would bring back some of those old cartridges like the .218 Bee and the .219 Donaldson Wasp and the .257 Roberts.

Ruger, I believe, did a comeback with the .220 Swift in their M77.

[Doc.2/47]

82Rigger-

The older .22 Hornets were barreled to use .223 bullets.I kinda think that the .22 Hi-power also used them but I don't have data at hand to confirm or deny this.

Not too long ago it wasn't too hard to find Thompson Center Contender pistol barrels in .218 Bee,.22 Hornet,or .222 Rem. Afraid I haven't been paying enough attention lately to know if this is still the case.Always thought that any one of these rounds would be a good combination with the T/C pistol but never have gotten around to trying them.

If the .257 Roberts is dead it just refuses to lie down.Still has a pretty good following amongst old-timers.Spect we'll still be seeing it as a limited production or rechamber item until after we're gone.

Happen to have a heavy barreled Win. M70 wearing a 15X Unertyl scope in .220 Swift (rechambered from .225Win.)sittin around here someplace.It's been known to reach out and touch things waaay out there.Doesn't see much use these days but spect it'd still do the job if asked.

Speakin of the .225,this is a very fine .22 round (doesn't give up much to the .22-250) to rechamber/rebarrel to if you ever run up on some of those old British single-shot actions (Snyder?) (falling block?)designed to use rimmed cases.Played a good bit with one of these that was a real tack driver.Think the action sold for about $30 and had had a rebarrel job.Think BSA also produced some actions suitable for conversion.

[Drywall]

Trav,
The old mauser we have talked about is 8mm. Can't remember if I told ya that or not.

[Keith_Hixson]

I'm so confused!
I thought this was a post by Some Minister bragging about
Church Growth.


Keith


P.S. I know Boo........!

[82Rigger]

You got it, bud! The "Hornet" was the .223 that I was trying to remember.

When the .220 Swift first came out (wasn't it in the 30's or 40's?)
the big problem was barrel life due to throat erosion. Wondering how the "modern" Swifts are handling this, with better steel alloys and ball powders.

I never had a Swift, but my favorite "tack driver" was a Rem 700 Varmint Special in 22/250. I floated the barrel, mounted a Weaver T-10 target scope with fine cross hairs and handloaded as precision as possible...reamed case necks, uniformed and deburred primer pockets, weighed charges to plus or minus ZERO, and seated bullets in a zero-runout die.

Got some REAL LITTLE BITTY 10 shot groups off a benchrest...well under a half inch at 100.

[colmurph]

When I lost the sight of my right eye to glaucoma I gave my son my Ruger #1 in .22-250 with a Unertl 20x Sniper Scope mounted on it. AWESOME varment rifle!
Now I'm learning to shoot all over again as a southpaw.

[Doc.2/47]

You got it Col.-
Improvise,adapt,overcome.Sounds like a truly fine rig.

82-
Yes,relatively short barrel life due to throat erosion was a widely talked about concern with the .220 Swift.Also with the 264 Win. Mag. and the bad press really hurt both of these rounds popularity.My thoughts on the matter:
1.Believe the problem was overstated to begin with.
2.Think careful bullet seating and powder selection can make a considerable difference.
3.Seems to me that even with very hard use a .220 Swift barrel would last 10-15 yrs.Most folks that like it enough to give it that kind of use wouldn't be all that upset about havein to get a new barrel.
4.It can always be loaded down to 22-250 velosities for general use and the hotter loads saved for special occasions.
5. The same barrel life concerns applied to the .220 Swift could-in all fairness-be applied to about any Weatherby cart. for the same reasons.They still seem to have a pretty good following.

The above are thoughts,opinion,and conjecture.The fact of the matter is that the .220 Swift mentioned has been providing good service since the early '70's and accuracy remains as good as ever.

Good Lord! With those kinds of groups it sounds like you could deplete the housefly population from 200yds.!

[82Rigger]

My groups were measured with a caliper across the widest part of the pattern, in other words from outside edge to outside edge.
A "perfect" group, by this type of measurement, would be .224 inches (all shots in the same hole).

You may know this already...in competition, groups are measured from the CENTER of the bullet hole. Thus, a "perfect" group would measure .000 inches.

When I was shooting, the benchrest 100 yard world record 10 shot group was .009 inches (measured center to center). I guess you'd have to look real close to see that the hole was a mite bigger than a single bullet hole!

I concur with your assessment on the throat erosion problem in the Swift. Another factor that makes a difference is whether the barrel is cold or hot. A heated barrel will erode much faster because the steel is softer. Not likely to be a problem while hunting, but could be for other types of shooting.

As a general rule, I found that my most accurate handloads were well below the maximum loads listed in the manuals. With that 22/250 my most accurate loads were around 15% to 20% BELOW the listed maximum.

[locksly]

The 220-swift was chambered in stainless-steel barrells to stop the problems with erosion in the throat of the barrell. Winchester developed a method of blueing stainless steel barrells so people would buy them as most people wanted blue barrells then. These days people want the stainless barrell bright so they can show it off. The rifle Doc has down there has shot a few crows at 390+ yards.and I can not remember how many groundhogs.