Faxon Gunner Barrels Velocity Comparison 18" vs 20" ??

[crusader18]

In choosing between the two lengths Faxon barrels with 5R rifling, using the same load how many FPS difference between the 18" and 20" barrel? The difference in weight is less than 5 oz, what would the extra two inches translate into in terms of increased velocity? Has anyone done a comprehensive analysis? Can someone who has both weigh in, or point me to some data?

[Lastrites]

Give or take maybe 40/60 fps total from what I've gathered.

[A5BLASTER]

25 to 50 fps.

[Kswhitetails]

A5 is closer to real; it'll be close to 25 an inch.

[LRRPF52]

With 18" shooting 123gr, I've normally chrono'd factory loads in the mid-high 2400fps range, think 2450-2500fps.

With 20" and 123gr, they're normally 2480-2550fps.

Sometimes there is overlap, depending on the rifling type.

20" is something to consider if you'll be shooting more long range down at lower altitudes, or if you want certain varmint projectiles to retain a little more speed in the closer ranges when hunting coyotes, but this can be addressed with bullet types and BC as well.

I originally wanted a 20" Grendel, and have built and shot a bunch of them, but have felt well-served with 3 different 18" Grendels because I live and shoot at pretty high altitudes as the norm. Since the air is thinner up here, barrel length doesn't matter as much as it does down near sea level.

[grayfox]

Ditto to the above. I have and have shot 16, 18, 20, as well as 12.5 and 22", faxon and nitrided as well as (others) CM/SS, and for the range 16-20" it has usually been 18-25 ft/s/inch. I say usually b/c each barrel has its own MV speeds, due to uniqueness and to such things as internal barrel frictions, so the comparison of two that differ in length won't be exact -- you can't exactly extrapolate but it will fall into that range. Your accuracy nodes for each should also be about that much difference but again it's a process of discovery, each barrel will tell you what it likes as far as MV.
Faxon's barrels are all nitrided IIRC so the MV increase that happens in a chrome-moly or SS over the first 50-150 rounds, doesn't typically happen for the nitrided barrel, it is what it is. Of course YMMV but this is what I've observed.

If MV is your object, get as long of a good quality barrel as you can tote/shoot/take care of. Like you say the delta in oz is not that much (will be a bit more than your 5 oz b/c you typically get a longer HG too).

The Faxon barrels have been good for me (I did move on to better ones though). However, a bad-mfr-barrel, or a cheap one, regardless of the length, is just so much of a tomato stake.

[crusader18]

Thank you for your input. As far as altitude goes, IIRC, we're mostly under 2,000 ft. mostly inside 200-300yds, but clearcuts can get pretty wide. Was thinking about those 129ABLRs Mark over at PR sells for Maine deer and wanted to know if the 20" would launch the heavier pill with substantially more velocity, as in enough to make a difference in terminal performance. at those ranges, 50 or so FPS probably doesn't huh? Beside the (factory)Hornady 123SSTs, which seem to get mixed reviews what else is out there that will do the job on big northern whitetails that someone who doesn't reload can buy?

[A5BLASTER]

Thank you for your input. As far as altitude goes, IIRC, we're mostly under 2,000 ft. mostly inside 200-300yds, but clearcuts can get pretty wide. Was thinking about those 129ABLRs Mark over at PR sells for Maine deer and wanted to know if the 20" would launch the heavier pill with substantially more velocity, as in enough to make a difference in terminal performance. at those ranges, 50 or so FPS probably doesn't huh? Beside the (factory)Hornady 123SSTs, which seem to get mixed reviews what else is out there that will do the job on big northern whitetails that someone who doesn't reload can buy?

There is like 90 something loads avalible to purchase. LRRPF52 will be along too post the list he has.

There's
Hornady
Nosler
Remington
PPU
Barnes
Federal
And a metric ton of small specialized shops that offer loaded ammo.

Northern whitetail aren't any harder to kill then southern witetails put a 85 to 130 grain bullet in its heart it will die.

Put a 85 to 130 grain bullet through its cns it will drop in it tracks.

For 300 and less my personal pick for factory hunting ammo would be the federal fusion 120 grain ammo.

Hope this helps sir.

[crusader18]

"If MV is your object, get as long of a good quality barrel as you can tote/shoot/take care of. Like you say the delta in oz is not that much (will be a bit more than your 5 oz b/c you typically get a longer HG too).

The Faxon barrels have been good for me (I did move on to better ones though)."

Thanks for your reply grayfox,
The primary function is as a hunting rifle and weight is a big factor, which is why I'm looking at the Faxon Gunner barrels. When you say you moved on to better barrels, I wouldn't mind paying a little more for something more precise and faster MVs, but the biggest factor for me is that long walk out/drag back to the truck. If there's other lightweight barrels out there that beat it, I'd love to know what to look at. I have a 20" PF upper with a Fluted Criterion barrel that feels like a cinder block compared to a pencil profile. It shoots beautifully at the range, but I wouldn't want to walk a mile through the woods with it. Ironically, that's what I bought it for, it's just too heavy though. The Faxon 18" according to them, weighs 1.62lbs, which is 1lb lighter than an 18" White Oak SPR barrel. Without spending $900 on a carbon fiber barrel, what are my other options?

[grayfox]

The one - if you want to call it - drawback with the mid-grade barrels like Faxon is some are good, and some are ok, especially with factory ammo.
I would suggest you look at a couple of other barrels: a criterion (Mark at PF has them but you could be looking at a wait) and Brownell's sells some too. Or Ballistic Advantage (the fluted ones), like at Arm0rAlly where they have a decent discount.
For 300 yds and under honestly an 18" should be plenty of length. Some guys will even do a 16er. Get a freebie ballistics program and do some playing around. I like to stay above a min of 1000 ft-lbs.
For factory ammo there are like A5 says 90+ loads out there.
In my BA barrels the 123 Sst Custom Hornadys shoot under 1-1.25" and the ballistics makes them a good load under 300 yds. There's also a new one from Barnes, in 115 gr Tac-tx with an opening min of around 1500-1600 (I like to stay about 200 higher than any publish mins to make sure it will open wide enough to do its work, as far as distance planning goes), or those 129 Ablrs or even 129 sst's. Fed fusions, with their more blunt noses, I'd stay under maybe 200 yds with. The 123 is definitely the leader in deer kills, fyi. AA has I think 120 Nosler BT's too.

Get the Grendel handbooks, Vol 1 and 2, in the vendor section under AR15 build box threads.
If you're not in snow or you have back problems (like I do) be sneaky and pull your rifle along in a cart, let the wheels carry the load!!

[crusader18]

The one - if you want to call it - drawback with the mid-grade barrels like Faxon is some are good, and some are ok, especially with factory ammo.
I would suggest you look at a couple of other barrels: a criterion (Mark at PF has them but you could be looking at a wait) and Brownell's sells some too. Or Ballistic Advantage (the fluted ones), like at Arm0rAlly where they have a decent discount.
For 300 yds and under honestly an 18" should be plenty of length. Some guys will even do a 16er. Get a freebie ballistics program and do some playing around. I like to stay above a min of 1000 ft-lbs.
For factory ammo there are like A5 says 90+ loads out there.
In my BA barrels the 123 Sst Custom Hornadys shoot under 1-1.25" and the ballistics makes them a good load under 300 yds. There's also a new one from Barnes, in 115 gr Tac-tx with an opening min of around 1500-1600 (I like to stay about 200 higher than any publish mins to make sure it will open wide enough to do its work, as far as distance planning goes), or those 129 Ablrs or even 129 sst's. Fed fusions, with their more blunt noses, I'd stay under maybe 200 yds with. The 123 is definitely the leader in deer kills, fyi. AA has I think 120 Nosler BT's too.

Get the Grendel handbooks, Vol 1 and 2, in the vendor section under AR15 build box threads.
If you're not in snow or you have back problems (like I do) be sneaky and pull your rifle along in a cart, let the wheels carry the load!!

I'd get laughed out of deer camp if I brought a cart to drag my rifle into the woods, you know how that goes. Like I said, I have a 20" fluted Criterion upper from Mark and like I said, it's beautiful and heavy(upper weighs a shade under 7lbs with scope), IDK if having him flute an 18" barrel for me would make that much of a difference.(Maybe getting rid of the muzzle brake and just going with a target crown) I'm not averse to spending the money, but since it's going to strictly be for hunting, I'm not expecting to put more than a few dozen rounds a year through it once I find a load it likes. Is there someone out there producing lightweight barrels above rack grade? I'm already using a light HG, so there's not much I can lose there. Any other suggestions?

[A5BLASTER]

I'd get laughed out of deer camp if I brought a cart to drag my rifle into the woods, you know how that goes. Like I said, I have a 20" fluted Criterion upper from Mark and like I said, it's beautiful and heavy(upper weighs a shade under 7lbs with scope), IDK if having him flute an 18" barrel for me would make that much of a difference.(Maybe getting rid of the muzzle brake and just going with a target crown) I'm not averse to spending the money, but since it's going to strictly be for hunting, I'm not expecting to put more than a few dozen rounds a year through it once I find a load it likes. Is there someone out there producing lightweight barrels above rack grade? I'm already using a light HG, so there's not much I can lose there. Any other suggestions?

Go shorter in barrel length 16 inch at the longest and have Mark profile the barrel to be as light weight as possible. Keep the .750 gas block profile.

Basically the same as a JP 18 inch grendel barrel but cheaper.

[Grendelshooter]

Give or take maybe 40/60 fps total from what I've gathered.

Exactly what I got today. Wolf 100gr, Hornady black 123bthp and 123eldm.
18? ARP vs 20? group buy, 10 shot strings.
Worked out to 30-ish/inch.

18? - 20?
2559 2622 -Wolf steel case 100gr
2417 2483 -Hornady Black 123bthp
2430 2496 -Hornady Black 123eldm

Jesus Christ how do you delete attachments?

[crusader18]

Go shorter in barrel length 16 inch at the longest and have Mark profile the barrel to be as light weight as possible. Keep the .750 gas block profile.

Basically the same as a JP 18 inch grendel barrel but cheaper.

I was just getting ready to email him and ask if he could profile an 18" mid gas, un-threaded muzzle and profile/flute it down to about 1.5lbs. I'm guessing if anyone could do that, it would be Mark. Don't know if barrel whip would start to be a problem, but Faxon advertises 1.62lbs on their Gunner profile, which is what caught my eye initially, plus I've had pretty good luck with their pencil in 5.56. If Faxon could do it, I'm sure Mark can.

[grayfox]

I'd get laughed out of deer camp if I brought a cart to drag my rifle into the woods, you know how that goes. Like I said, I have a 20" fluted Criterion upper from Mark and like I said, it's beautiful and heavy(upper weighs a shade under 7lbs with scope), IDK if having him flute an 18" barrel for me would make that much of a difference.(Maybe getting rid of the muzzle brake and just going with a target crown) I'm not averse to spending the money, but since it's going to strictly be for hunting, I'm not expecting to put more than a few dozen rounds a year through it once I find a load it likes. Is there someone out there producing lightweight barrels above rack grade? I'm already using a light HG, so there's not much I can lose there. Any other suggestions?

HAHAHA!! Doesn't really bother me much, I haven't done many camps, don't hike long trips when I hunt, and besides the deer don't seem to mind anyways .
But yeah, talk to Mark, go for a lightwt profile I'm sure he can do something for ya.
My 16er weighs about 7 1/2 lb, I can walk that one if I need to...