.223 Rem Sinterfire

[Wollychop]

Holy smokes. Just got back from the range. Really surprised by the results.

.223 Remington

Remington brass (fire formed)

Fired from a 24 inch Rem 700 1:12 twist

.224 diameter 36 grain Sinterfire Frangibles

Shot string:

23 Grains H 322
CCI 41 Primers
OAL: 2.238

----------
4510 FPS
4581 FPS
4561 FPS
4540 FPS
4458 FPS
4475 FPS
4523 FPS
4554 FPS
4494 FPS
4532 FPS
-----------

Grouping at 2" at 100 yards

Not too shabby! :laugh:

[jmz5]

I really like using the powdered metal bullets, they are cheap and accurate.

I like to use 23 grains of H335 with a 55gr.

I could probably push it hotter, but I like to conserve powder.

[Grantness]

Is that for real Wollychop? Wow. I didnt think .223 could get those kind of speeds w/ a 36gr bullet (or any bullet for that matter), let alone a sintered bullet. All of my experience tells me that Sintered bullets can't typically be pushed as fast as your average jacketed bullet...but, hey, I'd love to be proved wrong. Jebus, those are like .223 WSSM velocites!

Come on, you can admit it, you've been using nanolube on your barrel havnt you? :p :monkey: :laugh:

[Hobknob]

Dang! That's awesome...I'm gonna have to try that. You sure your chrony is working properly cause that does seem crazy fast for a regular .223?

[Wollychop]

Is that for real Wollychop? Wow. I didnt think .223 could get those kind of speeds w/ a 36gr bullet (or any bullet for that matter), let alone a sintered bullet. All of my experience tells me that Sintered bullets can't typically be pushed as fast as your average jacketed bullet...but, hey, I'd love to be proved wrong. Jebus, those are like .223 WSSM velocites!

Come on, you can admit it, you've been using nanolube on your barrel havnt you? :p :monkey: :laugh:

Yes, it is definitely for real.

Crisp recoil but clean flight and nice grouping. No signs of overpressure on cartridges. Like I said, it surprised me.

Nothing wrong with the chrony either, as I had three other loads I was also testing (50 grain varmint grenades, 40 grain v-max, and 55 grain fmjbt) and all hit the "right" velocities for the loads.

[romer522]

I thought like 3800-4k was doable with an AR, but 4500?


I'd like to see it hit something

[romer522]

What were you getting out of the 40gr Vmax?

[Wollychop]

That's the funny thing, I was only pushing the red tips at ~ 3400 FPS.

My wife and I were shooting, she was "monitoring" the chrony and I was firing while she recorded. We shot the V-Max's first, then the 50 grain Varmint Grenades (which Held 3077 FPS average) and then moved on to the sinterfire loads.

When she told me the first number I said something like "you're on crack" and then we kept shooting.

[romer522]

Maybe it has something to do with actual construction of the bullet at some funky lighting situation that made the 2nd detector on the chrono pick up the round before it normally would.

I thought it was hard to even find a powder capable of those velocities regardless of caliber.

[Wollychop]

Maybe it has something to do with actual construction of the bullet at some funky lighting situation that made the 2nd detector on the chrono pick up the round before it normally would.

I thought it was hard to even find a powder capable of those velocities regardless of caliber.

You know that's possible I guess. Maybe someone else should replicate?

[gw45acp]

the chrony readings are too consistent for it to be a fluke. Sometimes the muzzle blast from hypersonic loads can cause erroneous velocity readings, but I don't think that is the case because the readings would be all over the lot. I've read about peope getting 4000+ ft/sec from a similar rifle with light bullets.

EDIT: I checked my facts and it was a 22-250 using 36 gr VG's. My bad. He got no better than 4000 ft/sec on most powders, but one powder got him 4600+ out of a 24" Handi-Rifle and he couldn't believe it.

[Grantness]

For 223 Remington, Lee lists 25.5 grains of H322 as the max for a 40gr jacketed bullet. The velocity is 3574fps. Hodgdon lists the exact same figures for a 24" barrel. I just dont see how it could be physically possible to get an extra 1000fps w/ a bullet only 4gr lighter and w/ 2.5gr LESS powder. The kinetic energy would have to jump 42.7% from 1134ft/lbs (for a 40gr bullet at 3574fps) to ~1619ft/lbs (for a 36gr bullet at 4500fps) w/ less mass and less propellant.

The fastest load for a .223 WSSM I found in the Hodgdon Manual was 4362fps w/ 45.2gr of IMR 4064 under a 40gr nosler bt.

Hornady lists the fastest 223 WSSM load as 4600fps w/ 45.2gr imr 4064 under a 40gr VMax.

The fastest load in the Lee manual for a 220 Swift was 4470fps w/ 42gr of Acc 2420 under a 40gr jacketed bullet.

So, we see that those sorts of velocities are possible w/ certain cartridges and powders....but I just can't understand how thats possible with H322 and the 223 Remington case.

[Wollychop]

Hey, my feelings won't be hurt if it's wrong :laugh:

I would just like it to be copied / confirmed / debunked by someone else. I *know* that my chronograph works.

If they weren't going that fast, what would cause a chronograph otherwise operating correctly to create consistently incorrect readings with ONE type of bullet?

The only thing that I could think of is that maybe the fact that the 36 grain sinterfires are significantly longer than other bullets in that weight range with more bearing surface might be a contributing factor, if indeed they did reach those velocities.

[Grantness]

What type of chrono? Any unusual conditions? Really sunny, cloudy, humid, rainy, windy? Altitude? Skyscreens installed? How far away was the muzzle from the chronograph (i've noticed anything inside a yard or two causes big time problems w/ the FsN). Shooting at an odd angle could only make the bullet appear slower, right?, so that can't be a factor :ponder: You weren't shooting on full auto were you? Any worm holes in the vicinity? :laugh:

Does anyone think its possible that unburned powder could slip past the sintered bullet (which perhaps doesnt expand into the grooves like a jacketed bullet?) and catch a reading?

If the chrono wasnt level, could that make the bullet appear faster?

[Wollychop]

About 80 degrees, clear skies. Chrony was about 10 feet from the muzzle on a separate table.

If there was a wormhole I didn't notice it :laugh:

But maybe that's why we finished shooting before we started?

[gw45acp]

You should try it again about 15 feet from the muzzle to see if that gives you a significantly lower reading. Grant's analysis of 40 gr bullet velocity makes me think it may have been the blast wave being read by the chrony.

[Wollychop]

I'll definitely do that. Will have to probably be sunday though. Goin' on a little trip tomorrow.

[Esteves]

Who needs a 22-250?...

[Hobknob]

I wonder if the sinterfires have more resistance going down the barrel which allows the powder to continue building/maintain a high pressure throughout the bullet push sequence rather than having the bullet escape faster than the powder can expand to fill the new volume? just a thought, cause i'm no expert on internal ballistics.....i'm really just trying to think of a scenario that would explain it...cause i really really want those numbers to be true:)