The Chrono Don't Lie, Right?

[Flatland Shooter]

I just started reloading for .223 recently and I've fine tuned a load for long distance targets. Now I'm putting my efforts into finding a nice uberlight hosing load using the materials at hand.

This afternoon I chrono'd a load built with Nosler 50 gr SP bullets and 22.1 gr AA2230 powder. In the AA online reloading data, this is the "starting load" for this bullet and powder. This load should chrono at 3093 fps.

Accuracy is decent and recoil is quite nice. Fired around 30 rounds without a problem, Locks back the bolt on the last shot.

But per my chrono, this load clocks at around 2725 fps. Way below the nearly 3100 fps expected. The Shooting Chrony seems to read correctly with other ammo (XM193 measured at 3210 fps).

Both bullet weights and powder weights have been verified with a balance beam type scale and primers are recent vintage CCI SRP.

Its a sweet shooting load but is it safe? And any ideas why its running so slow.

Thanks.

Bill

[Dan Sierpina]

What is your barrel length? Most reloading book velocities come from 24 - 26 inch bolt gun barrels. All the gas is used to push the bullet down the barrel, not cycle an action. Consistent lighting for the screens, can make a difference.

[Flatland Shooter]

Its a BHW 18" barrel. It was 76 degrees and overcast with little to no wind.

What caused me to raise an eyebrow is the XM193 was within 30 fps of published data and my 77 gr long distance load was very close to published data. All three were run over the chrono in a 15 minute period.

The gun is zero'd at 100 yards with the 77 gr load. The XM193 shoots about 1-1/4" high and this hoser load shoots almost 2" high.

Is there a possibility that the length of the bullet passing over the screens would have an effect? In the past, this chronograph has given a little faster reading for 124 gr MG JHP when compared to official match chronographs.

Bill

Edited February 21, 2014 by Flatland Shooter

[JPeel]

My loads rarely match, or come close to the published data. Sounds like the load runs good and clears the barrel, so if you wanted a hoser load it sounds like you found one!

[kurtm]

That velocity sounds about right for that charge weight. 24-25 will get you closer to the 3050 range. That charge weight is way light for a 50 grain bullet.

Edited February 21, 2014 by kurtm

[Religious Shooter]

AA data is for a 24" and they were using WSR. Normally I'd expect 25-35 fps per inch.

You are at 3093-2725=368 fps; 368/6 = 61.3 fps per inch. I'd guess that some of the difference is because the probably used a fixture vs. semi-auto.

Some of the difference is probably because you used CCISR.

I don't have any data for WSR vs. CCISR. But Wolf 223 Primers vs. CCISR with 55's... the Wolf primers were 50 fps faster. Same load, different primers.

20" DPMS barrel, 25 grains A2230 with 55's (unknown primers), LC cases, gave me 3062 fps. Which is about 122.5 FPS/grain. 22.1 grains x 122.5 = 2707 fps. In the same ballpark as what you got.

There are also fast and slow barrels.

[outerlimits]

It sounds right to me. My 18" JP spits out 55NBT's at 3,029 with 24.9 of AA2230

[Flatland Shooter]

I checked again to be certain. The online reloading data has several 50 gr bullets with a starting load at 21.2 to 21.3 gr AA2230.

My concern was the low velocity I'm seeing and is it safe. Sounds like I'm OK.

Thanks.

Bill

[GM2B]

I have shot 1000's of 50 SP's and 55FMJs at 2300-2500 FPS just to reduce recoil. They run great!

[Flatland Shooter]

I have shot 1000's of 50 SP's and 55FMJs at 2300-2500 FPS just to reduce recoil. They run great!

Would you share the powder and load?

Running that load would put the recoil on par with a .22LR.

Bill

[GM2B]

I have used varget around 23.5 and now I am using BLC-2 around 24.0 I have to check. People have asked me that before and I dont ever remember! The gas is set to barely cycle the round and I use a lightened carrier and buffer which also helped reduce reciprocating mass. I really think it gives me a competitive edge in scored hits on paper.

[kurtm]

Don't use that load on small rodents....it will just make them mad! In typing this did you notice just a bit of shrinkage??

[KY1911]

Great thread. I just chrono'd my go to 3 Gun load today for the first time. Been shooting it for a year with long-range and hoser success, but never measured.

55 gr FMJ BT from a big box of 1,000 loose. 23 gr of H322 making 2710 avg. With my heavier barrel and brake, the rifle just doesn't move - up, down, forward, back - nothing. I like the load a lot.

[GM2B]

I looked up the load it is 22.0 varget with a 55fmj or 22.5 BLC-2 . keep in mind this is a light load for hoser close stuff. I run 24.0 of varget pushing a 77SMK for distance.