5.56 chamber shows more velocity than wylde chamber

[thesheepdog]

I have been testing a mk262 clone for weeks and here are some interesting results from the two guns I used to test velocity.

Gun #1:
16" barrel, 5.56 NATO chamber, 5R rifling, melonite treated.

Gun #2:
16" barrel, .223 wylde chamber, 3R rifling, melonite treated.

The velocity on the 5.56 was about 100fps faster than the .223 wylde;consistently higher.

Average velocity of the 5.56 chamber was 2665fps with a high of 2680 and a low of 2650.

The .223 wylde experienced much lower velocities.
Average was 2550fps with a high of 2570 and a low of 2530.

Thoughts? Comments?

All of the ammo was loaded the same.

 

[highbrow]

Might be the 5.56 chamber has more freebore, 2.550 vs ?2.430 for the Wylde. Just a thought.

 

[Mobuck]

There is little/no correlation between different barrels since the are simply too many variables. One bore might be slightly smoother or slightly tighter/looser or one rifling might create more drag. Even two identical rifles might show a significant difference in actual velocity with identical ammo.

 

[Cavitation]

My money is on the rifling difference.

 

[thesheepdog]

They're both 1:8 twist. Black hole weaponry claims their 3R barrels offer velocity increase. I don't know if it's the chamber or the rifling.

 

[AR15barrels]

1 sample of each chamber type is hardly enough sample size to make real conclusions.
The only conclusion you can make is that one barrel is faster than the other.
It probably has nothing to do with the throat.

 

[KO3422]

Agreed, I wish we had more barrels to test. It's probably the rifling difference.

 

[bfoosh006]

thesheepdog.... you might find this interesting...http://www.leverguns.com/articles/ballisticians.htm


To sum it up.... not all guns are "equal".

Look at the "S&W M19 #3" and "Colt Python #1"

 

[jglsprings]

Reloads or factory ammunition?

Bullet seated on the lands or off?

Two many variables to make your claim.