Alternate calibers? .17HMR, etc. Can't beat 'em, join 'em?

[m21sniper]

A guy i know just traded in his 6.5mm magnum because he cannot get ammo for it.

[Jeff Higgins]

Originally Posted by m21sniper

A guy i know just traded in his 6.5mm magnum because he cannot get ammo for it.

I knew a guy who had bought an M700 in 8mm Remington Magnum in the '70's when it first came out. By the mid '80's, when I met him, he could no longer buy ammo, even from Remington. He was forming cases from .375 H&H brass. Then he tried to hunt some African country with it, and couldn't get his ammo past customs because the headstamp didn't match the caliber stamped on the rifle. He wound up using a loaner .375 from the PH.

I'm extremely leery of oddball calibers. The current run of short magnums and super short magnums will, in all likelyhood, run this same course. They offer no practical advantage over anything else that has been out for much, much longer - notwithstanding the gun press's hype.

I see the .17 HMR in the same veign. Worse yet, it's a rimfire. At least with centerfires, we can reload for the oddballs. This is what happened with that old 5mm Remington; as a rimfire, when Remington quit making ammo, the rifles became useless.

As "oddball" as I get is with the .220 Swift and my black powder cartridges. The former is striclty a long range varmint gun / plinker, and the BPCR's are match rifles (although I have taken game with a few of them). None are hunting rifles that I would travel with. I handload for all of them, and have enough brass right now to last the rest of my life.

[m21sniper]

100% agreed. Just look at the .41 action express pistol cartridge that was all the rage in the early 90s.

Good freakin' luck finding ammo for that now.

Another guy i know had his CAR-15 converted to that 6.8mm round the US Army was evaluating. I told him all he did was ensure that when the spit hits the fan all he'll have is a club.

[BlueSkyJaunte]

Originally Posted by m21sniper

Another guy i know had his CAR-15 converted to that 6.8mm round the US Army was evaluating. I told him all he did was ensure that when the spit hits the fan all he'll have is a club.

The 6.8 SPC? I know a few guys who are big proponents of that but I'll pass. With 5.56 and 7.62x51 ARs I have both ends of the spectrum covered.

The only "bizarre" AR round that interests me is the .458 SOCOM. I've got brass, dies, and heads (most .45-70 gov't heads work fine) enough to last me a lifetime. Nothing beats the fun-factor of sending a 1/2 lb of lead downrange w/in 3 seconds.

[emcon5]

Originally Posted by m21sniper

The .17 has such a fast TOF that it is not really very much affected by wind drift on anything under about 200m IIRC.

At .17 Remington velocities, maybe. A 4000 FPS Hornady .17 HP will drift 4" at 200 yards in a 10mph crosswind.

A .223, using Federal's published numbers (for their cheap American Eagle 55 FMJ) drifts 4.3 at the same range conditions.

Can't find any published wind for any of the .17 HMR, but I worked backwards from the Published CCI numbers and came up with a BC of 0.126. Using that figure, the CCI 17gr @ 2550 FPS drifts 3.3 inches at 100 yards, and 15.3 at 200.

So the .223, which isn't exactly known for it's wind bucking ability has 1/3 the wind of the .17 HMR.

[Jeff Higgins]

Wind drift is a function of deceleration, not velocity. Deceleration is a function of ballistic coefficient, so we just skip a step and express wind drift as a funtion of ballistic coefficient. It's really not that easy, though, as BC changes for a given projectile with its velocity and atmospheric conditions (BC is far from a static number), but it's close enough for government work.

There is a common misperception that a very high starting velocity, achieved with a light for caliber bullet, will result in less time of flight and therefore less time for the bullet to be affected by a given wind. If only it were that simple. While giving up a bit in trajectory, that little .17 HMR would be a far more effective cartridge if it used a heavier bullet. Less wind drift, better velocity retention, and better terminal ballistics.

[targa911S]

The 22 grain .17 HMR has much better killing power, but less velocity. 5" drift at 100 yrds in 5 mph wind.

[m21sniper]

Originally Posted by BlueSkyJaunte

The 6.8 SPC? I know a few guys who are big proponents of that but I'll pass. With 5.56 and 7.62x51 ARs I have both ends of the spectrum covered.

The only "bizarre" AR round that interests me is the .458 SOCOM. I've got brass, dies, and heads (most .45-70 gov't heads work fine) enough to last me a lifetime. Nothing beats the fun-factor of sending a 1/2 lb of lead downrange w/in 3 seconds.

I'm not sure of the exact cartridge name, but it's the same one that the failed HK 416 fired.


I've always thought a .220 swift chambered M-16 would be HOT, but no one at DoD listens to me.

[m21sniper]

Originally Posted by Jeff Higgins

Wind drift is a function of deceleration, not velocity. Deceleration is a function of ballistic coefficient, so we just skip a step and express wind drift as a funtion of ballistic coefficient. It's really not that easy, though, as BC changes for a given projectile with its velocity and atmospheric conditions (BC is far from a static number), but it's close enough for government work.

There is a common misperception that a very high starting velocity, achieved with a light for caliber bullet, will result in less time of flight and therefore less time for the bullet to be affected by a given wind. If only it were that simple. While giving up a bit in trajectory, that little .17 HMR would be a far more effective cartridge if it used a heavier bullet. Less wind drift, better velocity retention, and better terminal ballistics.

Bro a .17 Rem has a faster TOF to 200 m than almost anything around. Since wind effect manifests over time, less TOF = less bullet travel.

But of course you are correct that heavier bullets drift less, all other things being equal.

[m21sniper]

Originally Posted by emcon5

At .17 Remington velocities, maybe. A 4000 FPS Hornady .17 HP will drift 4" at 200 yards in a 10mph crosswind.

A .223, using Federal's published numbers (for their cheap American Eagle 55 FMJ) drifts 4.3 at the same range conditions.

Can't find any published wind for any of the .17 HMR, but I worked backwards from the Published CCI numbers and came up with a BC of 0.126. Using that figure, the CCI 17gr @ 2550 FPS drifts 3.3 inches at 100 yards, and 15.3 at 200.

So the .223, which isn't exactly known for it's wind bucking ability has 1/3 the wind of the .17 HMR.

That's a function of the ballistic coefficient of the projectiles, not the starting velocities.

Hence the .17 rem drifting so much less than the lower BC .17s with comparable velocities.

[BlueSkyJaunte]

Originally Posted by m21sniper

I've always thought a .220 swift chambered M-16 would be HOT, but no one at DoD listens to me.

I can't imagine a full-auto 4000 fps round. Hot indeed. How's the recoil on it? Never fired it myself.

[m21sniper]

It's pretty light. Certainly less than an AK 7.62x39 round.

[legion]

Eh. If .17 HMR disappeared tomorrow, I'd just have the rifle rechambered for .22 WMR. Literally all it would take is changing the barrel, as .17 HMR is a necked-down .22 WMR case...

[BlueSkyJaunte]

All this talk of fast rimfires got me looking around for an autopistol in either .17 HMR or .22 WMR. Mostly because I like the concept of the FNH Five-seveN (light, high-velocity bullet in a handgun) but don't care for the plastic.

I found this, which really started the wheels turning:

http://www.excelarms.com/1911conversionkit.html

[targa911S]

That IS pretty slick, and not a bad price.

[lowyder993s]

Originally Posted by targa911S

Here are my "evil twins of varmint death".

Top Howa 1500 in 22-250. Bottom Savage 93 in .17

I feel like a golfer when I go out. I have a double case and take them both. Over 150 yards I shoot the 22-250.


HMR



As a side note. for the .17 HMR I would highly recommend the BSA sweet 17 scope. I know, I know BSA's are crap, but this one has the elevation calibrated in yrds rather than clicks and it is calibrated for the ballistics of the .17- 17 grain cartridge. I like mine a lot. You just dial the yardage your focus gives you and BANG!, another dead groundhog!

OK...you better not be wrong!!! Just picked up 1 of these, shot another guys .17 they are a gas to shoot. Stupid accurate, inside 100yds, take their eyes out everytime. Now...where's a good place to find the sweet 17's? Was looking at swarovski and zeiss to put on top, but doesn't really pencil out for shooting squirrels and such.

[aigel]

Get an elite series Bushnell scope. Made in Japan. Nice optics for the $.

George

[emcon5]

There is a warning from Remington not to use their .17HMR ammo in an autoloader, and Remington is recalling all of their model 597 .17 HMR rifles.
http://www.remington.com/safety/17_HMR_Ammo_notice/default.asp

CCI has a similar warning about using 17HMR in a self-loader:
http://www.cci-ammunition.com/safety/safety_notice.aspx

Originally Posted by m21sniper

That's a function of the ballistic coefficient of the projectiles, not the starting velocities.

Hence the .17 rem drifting so much less than the lower BC .17s with comparable velocities.

It is both, actually, but the higher velocity of the .17 masks somewhat how much the .17s suck in the wind. In my American Eagle .223 example above, if the .17 was launched at the same velocity as the .223 (3240fps) it would still have half again as much wind, 6.4" vs 4.3" of drift at 200 in a 10mph wind.

He also isn't talking about .17 Remington though, he is talking about .17 HMR, which uses a lighter bullet (17 vs 25 grains) and much lower muzzle velocity (2550 vs ~4000fps). The BCs of 17 cal bullets all suck, and they all perform poorly in the wind, regardless of velocity.

Bro a .17 Rem has a faster TOF to 200 m than almost anything around. Since wind effect manifests over time, less TOF = less bullet travel.

But of course you are correct that heavier bullets drift less, all other things being equal.

Even when things aren't equal. For example, 2 loads

.17 Remington, 25gr Hornady HP, 4040 fps.
6.5-06, 140gr Hornady AMAX, 2818 FPS.

At 100 yards, in a 10MPH 90º wind:
17 has a Time of flight of .081 seconds, is still going 3428fps, and has drifted 1.1".
The 6.5 has a TOF of 0.11 seconds, is traveling 2655fps and has drifted 0.6"

At 200 yards in the same conditions:
17 has a Time of flight of .176 seconds, is down to 2889 fps, and has drifted 4.9".
The 6.5 has a TOF of .226 seconds, is traveling 2495 fps and has drifted 2.4"

So even though the .17 is still traveling faster at 200 yards than the 6.5 was at the muzzle, it still has twice the wind.

Time of flight isn't as important as people think it is. Even a marginally better bullet, the 55gr .224 Sierra Blitzking (with a BC of .264 at this velocity, compared to .187 for the .17) @3100fps has better windage (1.1" @ 100yds, 4.6" @ 200 yds) as the .17 even though it leaves the barrel nearly 1000fps slower.

[targa911S]

Sweet 17's are all over ebay. Trust me it's the right scope for that gun. Get the 6x18x40. they use med high to high mounts too.

[lowyder993s]

Originally Posted by targa911S

Sweet 17's are all over ebay. Trust me it's the right scope for that gun. Get the 6x18x40. they use med high to high mounts too.

THx...sniping 1 right now