Shorter Barrel 223 data

Hello Folks

I recently changed from an 17.75"/450mm Bergara B14 EH stainless barrel to a Bergara B14 St chrome moly barrel at 16.5"/420mm, both in 223.

The 16.5 is still being worked up but initial velocities are very interesting (to me at least!) when compared with the 18" (nominal) given that I have some direct comparisons, with more to come. Most samples are 10 rounds.

Fiocchi Factory (Red box) 55gn 16.5" 3030fps 18" 2982 (cool day) 3020 (hot day) fps
Sako 55gn. 16.5 2990 fps 18" 2984fps
ADI 62 gn. 16.5 2857fps 18" 2848fps

I'm not looking at this from the perspective of maximum speed, rather that two otherwise pretty much identically made barrels from the same company can be different!

I was having a play with quickload this afternoon to compare some potential powders. 16 inch barrel vs 18 inch (gimp's load). Something I noted was quickload had 97.3% propellent burn in the 16" for 2206h. Probably why 16" is a common length for AR-15 variants.

@Hahn which load of mine?


I have a lot of data from various 16 & 18 inch 223 barrels with different loads, there can be significant variance within a barrel length - 100fps less between a factory new production 700 barrel at 18" vs my 18" cut rifled barrel with the same load for example

The factory Remington barrel shoots extremely well however

@Hahn

It really depends on the gas system too.

Rifle length, mid length, carbine length or pistol length gas systems.

14.5" was another common length too but alas no more.
@Tentman I do recall looking at 223 data and it showed in the heavier bullet weights especially like 62+ that gppd old 2208 gave better fps than 2206H

2208 is compressed usually with heavier bullets to get good speed which is a slight pain

I've also been warned Gimp that for the heavier bullets using 2208 you need a longer barrel too? I've never reloaded for 223 when I had one but when i get another one I will reload for it

2208 works fine from 18 inch and does give similar, sometimes better, speed compared to 2206H

@gimp I found your load in the 223 thread for an 18" barrel, 25gr 2208 with 80eldms for 2800fps. @Rock river arms hunter Interestingly QL shows 2206h as faster and more efficient than 2208. I haven't found QL that accurate with my current loads but it gets me into the ballpark.

Ah yep, I am now using 24gr of 2206H, although that may change as I finish up an old 500gm container of 06H and begin using a new 4KG

That seems mild compared to your 2208 load. Are you still going 2800fps?

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Originally Posted by Rock river arms hunter

I've also been warned Gimp that for the heavier bullets using 2208 you need a longer barrel too? I've never reloaded for 223 when I had one but when i get another one I will reload for it

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The only thing I can see changing with length is amount of propellant burnt. So I guess in theory the best powder for a given projectile in a long barrel will also work best in a short barrel.

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Originally Posted by Hahn

That seems mild compared to your 2208 load. Are you still going 2800fps?

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Nah 2700 average, it doesn't make any difference. Both loads are at or around book max, although with a longer OAL so pressure should be lower, in theory. No pressure problems with either anyway

Yeah I see at 67mm oal you have another 8700ish psi before QL max. Could go to 25gr 99% full case and still be under 62000psi. 98% burn. Probably no real world advantage as you say though.

I may increase the charge weight slightly to increase my effective range (range at which projectile retains >1800fps) once I open my new shiny 4kg jug - however I also have other rifles with which I can shoot deer at 400+ m so it doesn't really make any difference

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Originally Posted by Tentman

Hello Folks

I recently changed from an 17.75"/450mm Bergara B14 EH stainless barrel to a Bergara B14 St chrome moly barrel at 16.5"/420mm, both in 223.

The 16.5 is still being worked up but initial velocities are very interesting (to me at least!) when compared with the 18" (nominal) given that I have some direct comparisons, with more to come. Most samples are 10 rounds.

Fiocchi Factory (Red box) 55gn 16.5" 3030fps 18" 2982 (cool day) 3020 (hot day) fps
Sako 55gn. 16.5 2990 fps 18" 2984fps
ADI 62 gn. 16.5 2857fps 18" 2848fps

I'm not looking at this from the perspective of maximum speed, rather that two otherwise pretty much identically made barrels from the same company can be different!

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Greetings,
You would expect a difference of around 30 fps between the two barrels with the longer one the faster all else being equal. All else is seldom equal though. The round count, if known, would be interesting as would has either been chopped?
GPM.

Only 30 mm offence in length. While this could make a small difference to velocity achieved with some loads, internal barrel and chamber dimensions, tolerances and finish could be more impactful as you suggested T’man.


Sent from my iPhone using Tapatalk

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Originally Posted by grandpamac

Greetings,
You would expect a difference of around 30 fps between the two barrels with the longer one the faster all else being equal. All else is seldom equal though. The round count, if known, would be interesting as would has either been chopped?
GPM.

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The shorter barrel is brand new, round count is currently 50. The round count on the longer barrel is about 400 (although some of the recorded velocities go back to its "break in" period).

Im thinking of now running a test on the new short barrel to see if the accuracy improves over its break in. I was thinking to load 100 rounds of cheaper components. Shoot a 10 shot group. 10 also of factory as a control. Blast off 20 rounds at gongs/hares etc. Shoot the 10 round tests again. Blast off 20. Test 10. Blast off 20, test 10. This would take the barrel to just over 200 rounds, which is when "the internet" says it should be fully broken in and shooting at its best (for a cheaper factory grade barrel). Thoughts on this guys?

Cheap components would be bulk Hornardy 55s over 748 powder. Id be interested to know if statistically speaking a 10 shot group is enough @gimp etc ??

The barrels are both at factory length. They borescope like factory barrels, nothing like a cut rifled and highly lapped custom grade barrel

I have a new barrel with 92 rounds on it. Precision for 10rd groups appears to be identical now vs when I started shooting it (at about 40 rounds). (Not .223 !!)

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Originally Posted by Tentman

Cheap components would be bulk Hornardy 55s over 748 powder. Id be interested to know if statistically speaking a 10 shot group is enough @gimp etc ??

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10 shots tends to give you a reasonably good idea of the true mean radius in my experience

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Originally Posted by gimp

I have a new barrel with 92 rounds on it. Precision for 10rd groups appears to be identical now vs when I started shooting it (at about 40 rounds).

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What is the barrel manufacture?

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Originally Posted by Tentman

What is the barrel manufacture?

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Brux

Quote:

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Originally Posted by Tentman

The shorter barrel is brand new, round count is currently 50. The round count on the longer barrel is about 400 (although some of the recorded velocities go back to its "break in" period).

Im thinking of now running a test on the new short barrel to see if the accuracy improves over its break in. I was thinking to load 100 rounds of cheaper components. Shoot a 10 shot group. 10 also of factory as a control. Blast off 20 rounds at gongs/hares etc. Shoot the 10 round tests again. Blast off 20. Test 10. Blast off 20, test 10. This would take the barrel to just over 200 rounds, which is when "the internet" says it should be fully broken in and shooting at its best (for a cheaper factory grade barrel). Thoughts on this guys?

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Given that bullet-barrel interactions are only one part of the puzzle of dispersion, and bullet quality is another part - possibly larger - this test may not demonstrate anything as far as "testing if accuracy improves"


To see a difference (improvement) in precision of the order that you might reasonably expect (0 - 10 % change in mean radius?) from barrel "break in changes", you'd likely need massive sample sizes to have confidence in the result even if you used good quality bullets and ammunition. What you might demonstrate is that there is no meaningful difference that can be established, so people shouldn't worry about it

Here I am derailing another thread getting on this topic, but it is really sensible to think in terms of "requirements" and meaningfully test whether the system meets those then move on, rather than thinking about precision optimisation without an acceptance threshold


For example these 3 10rd groups (of 3 different powders loaded with the same bullet) are all different sizes, however the precision of all 3 is functionally more or less the same - 0.05-0.06 MRAD mean radius.


Attachment 260485

I don't actually care if one is "better" than the others. The test is - do they meet requirements? They all do, for precision - the predictive O95 is 0.2 - 0.24 MRAD, but the error bars mean we can't say there's actually any difference. Either of these values meets my requirements threshold - neither of these values produces a meaningful difference in hit probability at long range. I can select the load that meets my other requirements. If they all do, great. Only 1 of these 3 powder loads met all of my requirements. It is the first group below the aiming point dot. Load development completed - off to kill things and compete.

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Originally Posted by gimp

I have a new barrel with 92 rounds on it. Precision for 10rd groups appears to be identical now vs when I started shooting it (at about 40 rounds). (Not .223 !!)

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No, you cant do that. Its cruel. Reveal.

Here is some velocity data with 2x 16" .223 and my 18" - 3 different loads, all 10rd averages

62gr bullet


Load 1 Load 2 Load 3
18" (mullerworks) 2902 2863 2955
16" 1 (tikka) 2813 2772 2854
16" 2 (trueflite) 2811 2796 2836