Looking at an AR

[Captain Hook]

To be honest, I don't know. What are the factor requirements/specifications for competitions and how do the velocities from different barrel lengths compare to those factors?
(Sorry for asking possibly trivial questions, but I am new to this part of the game)

I missed the factor question, and I doubt it unless you're hand loading to dangerous pressures.

[Brendank]

Seeing that you mentioned both the 14.5" and 10.5" variants, I'd be curious to see what the 14.5" price would be. The one I have seen recently was the 10.5". Originally I thought I would get the 14.5", as it felt like the perfect length for me for use in 3-gun and IPSC. But after feeling the 10.5" version I must say I am tempted to go that route instead.

Why would you choose the one or the other?

Around R16K retail.

[Stevin]

14.5" is a great general purpose rifle, the extra length of barrel adds to velocity.

10.5" is a great cqb rifle, but you loose a lot of velocity for a neat handy rifle.

I should have granted an 11.5" when they first landed.

The reason most mil units have moved away from 10.3 / 10.5 is cause they have excessive bolt speeds and tend to wear the rifles quicker.
Seals, and US Army have both moved to 11.5 models (from different manufacturers) to mitigate some of that excessive bolt speed by increasing the dwell time.

When going near 10" I would seriously consider something like 300blk. At the same barrel length you are putting way more energy on target, not that paper cares, but still.

[Stevin]

Will the 10.5 make factor? This might become a problem if you want to become competitive.

No it won't. Shortest barrel I would be comfortable trying to push to make factor with would be a 13.7 inch. I can be done with a 12.5 but you would be loading really hot ammo for no real benefit ito sport.

[wave.jaco]

No it won't. Shortest barrel I would be comfortable trying to push to make factor with would be a 13.7 inch. I can be done with a 12.5 but you would be loading really hot ammo for no real benefit ito sport.

So, what are the factor requirements for typical competitions the rifle might be used in? I.e. what factor values, velocities, etc?

[PeaceOfficer]

The reason most mil units have moved away from 10.3 / 10.5 is cause they have excessive bolt speeds and tend to wear the rifles quicker.
Seals, and US Army have both moved to 11.5 models (from different manufacturers) to mitigate some of that excessive bolt speed by increasing the dwell time.

When going near 10" I would seriously consider something like 300blk. At the same barrel length you are putting way more energy on target, not that paper cares, but still.

Thanks for the insight

[MrK]

So, what are the factor requirements for typical competitions the rifle might be used in? I.e. what factor values, velocities, etc?

Minimum factor for minor rifle is 150 and for major 320. 150 factor with a 55gr bullet means you need a minimum velocity of 2728 fps, but nobody loads to exactly make minimum factor so you should be looking at 2800 fps at least which gives you a factor of 154. Still quite a narrow margin for error.

Shooting 62 gr bullets needs 2500 fps to make 155 factor.

[FNBROWNING]

14.5" is a great general purpose rifle, the extra length of barrel adds to velocity.

10.5" is a great cqb rifle, but you loose a lot of velocity for a neat handy rifle.

I should have granted an 11.5" when they first landed.

The LM6 muzzle blast is brutal and thats around 11 inches. The LM5 with a 13.1 inch is still loud but far more tolerable. The 14.5 inch AR is a nice length. FNM 55gr runs around 3150 or 3125 fps out of this length. PMP 55gr out of a 20 inch AUG gives 3231 fps, so you are not giving up that much.

[Stevin]

Minimum factor for minor rifle is 150 and for major 320. 150 factor with a 55gr bullet means you need a minimum velocity of 2728 fps, but nobody loads to exactly make minimum factor so you should be looking at 2800 fps at least which gives you a factor of 154. Still quite a narrow margin for error.

Shooting 62 gr bullets needs 2500 fps to make 155 factor.

I shoot 62gr at 2900ish fps, and 55gr at 3100ish from a 16".
Prefer it as it has more gas to drive the comp the way I like.

[Stevin]

The LM6 muzzle blast is brutal and thats around 11 inches. The LM5 with a 13.1 inch is still loud but far more tolerable. The 14.5 inch AR is a nice length. FNM 55gr runs around 3150 or 3125 fps out of this length. PMP 55gr out of a 20 inch AUG gives 3231 fps, so you are not giving up that much.

You are giving up a round 25fps per inch in 5.56. It's really well documented.