Very Quick Barrel Length Test

[bladeracer]

I just did a very quick barrel length comparison.
My 25" BSA Sportsman 5 and my 18.5" Henry 001.

20200123_180515b.jpg (884.8 KiB) Viewed 2979 times

Barrel lengths measured with a .20-caliber rod against the bolt face are 640mm (25.2") and 472mm (18.6").
Both rifles would have had a similar amount of ammo through them, the BSA was barely used by a family member who bought it new when he was a kid, the Henry I bought new in March 2018 (but I doubt BSA ever imagined their rifle would ever see 1850fps).
CCI Standard Velocity - https://cci-ammunition.com/products/detail.aspx?use=1&loadNo=0032
CCI Quiet HP - https://cci-ammunition.com/products/detail.aspx?use=1&loadNo=0970
CCI Copper-22 - https://cci-ammunition.com/products/detail.aspx?use=1&loadNo=925CC
These are listed at 1070fps, 710fps, and 1850fps.

Velocity test .22LR.jpg (37.12 KiB) Viewed 2979 times

Yes, I checked the figures for the Std Vel and both riles totaled identical velocity across five shots!
So, the 25" barrel loses about 30fps over the 18.5" with the low-velocity Quiet.
Both are identical with the Standard Velocity.
But the long barrel gains about 180fps with the Copper.

https://www.youtube.com/watch?v=HjwzxgVKrMU

[bladeracer]

Velocity test .22LR.jpg (37.12 KiB) Viewed 2963 times

Just to clarify the chart that I threw together in seconds.
I took out two rifles with 18.5" and 25" barrels, and fired five rounds each of three types of ammo in the very low range, the very high range, and the mid range of .22LR velocities across the chrongraph. The muzzles were 500mm from the first sensor on the chronograph, and I fired them into a block of end-grain firewood just behind the chronograph. As I was more interested in the extremes I fired the CCI SV first to warm the barrel, then the Quiet, then the Copper.

The Henry 18.5" with the Std Vel gave me 1064fps to 1088fps, for a mean of 1076fps, Extreme Spread of 24fps. The BSA 25" gave me 1052fps to 1098fps, also a mean of 1076fps, ES of 46fps. The doubled ES may be a very good reason to keep a shorter barrel, the ammo is very likely optimised for 18" barrels. I've never scoped the BSA but over open sights it's a very accurate rifle. I can't believe the bullet is making a steady velocity through that last seven-inches, so I might have to do this with a 20" barrel as well.

With the Quiet, the short barrel gave me 675fps to 741fps, mean of 707fps, ES of 66fps. The long barrel gave me 655fps to 715fps, a mean of 674fps, ES of 61fps. The longer barrel loses 33fps down the last seven-inches of bore friction, the short barrel makes 7.5% more velocity.

With the Copper-22, the short barrel gave me 1589fps to 1707fps, mean of 1646fps, ES of 118fps. The long barrel gave me 1804fps to 1846fps, mean of 1824fps, ES of 42fps. The longer barrel makes 178fps more than the short barrel.

The ES of 24fps for the CCI SV in the 18.5" barrel is a good example I think of why it shoots so well for me. The ES of 118fps(!) for the Copper-22 in the 18.5" barrel is a good example of why it does not shoot so well for me That's a full 7.5% variation in velocity!

[SCJ429]

No flys on you Blade, nice work and interesting results.

[bigpete]

Thanks for posting that,certainly interesting results

[Blr243]

Republican. U owe blade 2 cartons for his work

[in2anity]

Fast powder in the 22lr cartridges right? (negating velocity gains from long barrels)

[bladeracer]

Fast powder in the 22lr cartridges right? (negating velocity gains from long barrels)

Very fast powder due to its extensive use in pistols as well.
Even an 18" barrel .22 only has two-thirds of a cubic inch of volume in which to convert one grain of powder into 12,000 pounds of pressure, in about one-thousandth of a second. A six-inch barreled handgun has less than one-quarter of a cubic inch of volume.

[bladeracer]

I had a moment to put some CCI SV through the Norinco 20" (498mm) barrel just now. Sun is gone so was a bit hard to get good readings, fired ten, got seven readings. I had the chrono set up at 90-degrees to get some light coming into the sensors. 1064fps to 1084fps.
1080
1083
1080
1064
1070
1084
1066
Mean is 1075fps, ES of 20, SD of 8.
So virtually identical to the 18.5" barrel with the 1070fps ammo.
I'll try to do the Quiet and Copper tomorrow.