The great barrel length debate AGAIN!

bm11

bm11

Gunny Sergeant
Full Member
Minuteman
Jun 18, 2010
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Maine
#1
I am working on trading for a GAP AR-10 in .260 as we speak. I have read a lot on the subject, and I know that with a .308, you don't lose hardly any velocity going from 26" down to 20," and only a bit going from 20" to 18"

The gun I would be getting has a 24" barrel on it, and I would be chopping it down and threading it for my can. I would like to go to 18," but don't know enough about the performance of a .260 in a gas gun out of that length barrel. Anyone done any chrono work with this caliber in this platform?

Thanks,

-Bob
 
#2
Re: The great barrel length debate AGAIN!

OK, well I just sealed the deal on this. I need to figure it out now I guess. I could always just thread the 24" that's on it, but I would prefer the handier length of an 18" or 20".
 
#3
Re: The great barrel length debate AGAIN!

I had a 26 inch 260 and we cut the barrel down to 20, the 308 parent case is not near as picky as the 260 is about barrel length, 260 velocity suffers greatly at 20 inches
 
#4
Re: The great barrel length debate AGAIN!

Why did you choose 260 over 308? If it was for the better ballistics, then why would you want to negate the advantage. 6.5's like their speed....

I have a POF 6.5 Creedmoor and if I could swap my 20" for a 24" inch barrel I would in a heartbeat!
 
#5
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Why did you choose 260 over 308? If it was for the better ballistics, then why would you want to negate the advantage. 6.5's like their speed....

I have a POF 6.5 Creedmoor and if I could swap my 20" for a 24" inch barrel I would in a heartbeat!</div></div>

Because you are under the impression you're gonna compete in F Class with it, when clearly that is not the purpose.

if you run the number we had gathered with the 18.5" 260 you will see, ballistically you still have a mild advantage over a 308 pushing a 155gr bullet at 2950fps. Not in elevation but in wind you still retain an advantage. So...

Ask yourself what am I trying to accomplish and then run the numbers -- clearly there is still an advantage over a 308, in a smaller lighter package. So in my opinion is a win.

Sure speed wins, but if you know your dope and understand your rifle and what you are doing, the advantages balance out. It's why there are always at least one 308 in the Top 10 at the SH Matches... because even with an open field, guys shooting 243s, and 260s, the competent shooter with a 308 can still perform alongside the wind cheaters.

A 20" 260 will always have an advantage over a 308 - its black and white. Unless you are going to run in F Class speed is not always as necessary as people think. Wanna shoot F Class -- get every single fps you can squeeze out of the rifle, but for anything else, especially tactically, light is right and the best bullet for the mission at hand.
 
#6
Re: The great barrel length debate AGAIN!

Valid points as usual, and I overshot the main point of bm11's question-that it was a chop for a can. In that respect, I'd keep the GAP chambered and crowned 260 barrel as is and get a 18" done up for the can and have the best of both worlds, rather than chop what is already a barrel that shoots well.

I don't "compete" in F-Class, rather I'm a civilian that shoots precision matches and I haven't felt hindered yet by a full length barrel. As you mentioned, the advantages "balance out", but for my style of shooting I'd rather the advantage stay as wide as possible.

I'd be willing to bet that there's always more than one full length (24"+) barrel in the top ten at the SH matches too.
 
#7
Re: The great barrel length debate AGAIN!

A couple of good points there. Damn. I really wanted to go with a .308, but the right trade came up on a .260. I'm not much of a handloader yet, so I'll be running factory ammo for now, and it kind of sucks a bit to lose some of the advantages of the lighter caliber by chopping it.
 
#8
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">
sobrbiker883 said:
if you run the number we had gathered with the 18.5" 260 you will see, ballistically you still have a mild advantage over a 308 pushing a 155gr bullet at 2950fps. Not in elevation but in wind you still retain an advantage. </div></div>Frank, what muzzle velocity were you getting out of that 18.5 inch barreled .260?
Click to expand...
 
#10
Re: The great barrel length debate AGAIN!

Sounds like the "can" may be “mission creep” more important than shot placement

There is a definite requirement for a suppressed long gun... but I have a hard time seeing the need outside of shooting targets that will shoot back.
My last unit had “cans” for every weapons system in inventory. The only time we used them was to establish dope and when a real world requirement made their use advantageous.
+1 on leaving the gun as is.. You’ll find something else to put the suppressor on.
 
#11
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Valid points as usual, and I overshot the main point of bm11's question-that it was a chop for a can. In that respect, I'd keep the GAP chambered and crowned 260 barrel as is and get a 18" done up for the can and have the best of both worlds, rather than chop what is already a barrel that shoots well.

I don't "compete" in F-Class, rather I'm a civilian that shoots precision matches and I haven't felt hindered yet by a full length barrel. As you mentioned, the advantages "balance out", but for my style of shooting I'd rather the advantage stay as wide as possible.
<span style="font-weight: bold">
I'd be willing to bet that there's always more than one full length (24"+) barrel in the top ten at the SH matches too</span>.</div></div>

At lot more not in the top 20 as 4 extra inches and 80 more fps never won anyone the match.

The better shooters are in the top ten. Guys chasing stats aren't practicing to their full potential, they are hoping the round takes up the slack for their lack of focused practice.

People running numbers and extolling speed aren't out practicing, they are doing endless cycles of load development and staying at home because they are not ready yet. Then as soon as they hear someone won something with a different bullet they are starting all over crunching new data in order to win.
 
#12
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Valid points as usual, and I overshot the main point of bm11's question-that it was a chop for a can. In that respect, I'd keep the GAP chambered and crowned 260 barrel as is and get a 18" done up for the can and have the best of both worlds, rather than chop what is already a barrel that shoots well.

I don't "compete" in F-Class, rather I'm a civilian that shoots precision matches and I haven't felt hindered yet by a full length barrel. As you mentioned, the advantages "balance out", but for my style of shooting I'd rather the advantage stay as wide as possible.
[
I'd be willing to bet that there's always more than one full length (24"+) barrel in the top ten at the SH matches too[/b].</div></div>

At lot more not in the top 20 as 4 extra inches and 80 more fps never won anyone the match.

The better shooters are in the top ten. Guys chasing stats aren't practicing to their full potential, they are hoping the round takes up the slack for their lack of focused practice.

People running numbers and extolling speed aren't out practicing, they are doing endless cycles of load development and staying at home because they are not ready yet. Then as soon as they hear someone won something with a different bullet they are starting all over crunching new data in order to win. </div></div>

So true. Well said.
 
#13
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Steve_Aryan</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Valid points as usual, and I overshot the main point of bm11's question-that it was a chop for a can. In that respect, I'd keep the GAP chambered and crowned 260 barrel as is and get a 18" done up for the can and have the best of both worlds, rather than chop what is already a barrel that shoots well.

I don't "compete" in F-Class, rather I'm a civilian that shoots precision matches and I haven't felt hindered yet by a full length barrel. As you mentioned, the advantages "balance out", but for my style of shooting I'd rather the advantage stay as wide as possible.
[
I'd be willing to bet that there's always more than one full length (24"+) barrel in the top ten at the SH matches too[/b].</div></div>

At lot more not in the top 20 as 4 extra inches and 80 more fps never won anyone the match.

The better shooters are in the top ten. Guys chasing stats aren't practicing to their full potential, they are hoping the round takes up the slack for their lack of focused practice.

People running numbers and extolling speed aren't out practicing, they are doing endless cycles of load development and staying at home because they are not ready yet. Then as soon as they hear someone won something with a different bullet they are starting all over crunching new data in order to win. </div></div>

So true. Well said. </div></div>

I'm extremely guilty of this too.
 
#16
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BCP</div><div class="ubbcode-body">Take it out and shoot it. If it does what you want it to do, fine; if not then worry about having it cut down. GAP AR10's are really nice rifles so I don't think you'll be disappointed. </div></div>This doesn't change the fact that I want to use my suppressor on it. I would be fine threading it, but it seems like if I am going to send it out to thread it, I might as well chop it in the process. Savvy?
 
#17
Re: The great barrel length debate AGAIN!

If you are going to dedicate the weapon to the suppressor go as short as possible with reliable weapons function.

subtract 6" and 1 lb (estimated) add 9" and 1.5 lbs (estimated)

negatives... drop a couple hundred FPS, risk messing up a shooter, more wear and tear on the gun

positives... sound and blast signature reduced

Bolt gun with suppressor vs gas gun with suppressor

We ran 10.5” uppers with suppressed M-4s, and experienced reduced barrel life with high density shooting… the extra gas and heat started to melt the gas port
 
#18
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ssatt68</div><div class="ubbcode-body">If you are going to dedicate the weapon to the suppressor go as short as possible with reliable weapons function.

subtract 6" and 1 lb (estimated) add 9" and 1.5 lbs (estimated)

negatives... drop a couple hundred FPS, risk messing up a shooter, more wear and tear on the gun

positives... sound and blast signature reduced

Bolt gun with suppressor vs gas gun with suppressor

We ran 10.5” uppers with suppressed M-4s, and experienced reduced barrel life with high density shooting… the extra gas and heat started to melt the gas port
</div></div>The can is 14 oz (titanium) so if your weight estimations are correct, than I should break even. I don't think I want to go down to 16" on a .260. It seems like "too much" of a compromise in muzzle velocity.
 
#19
Re: The great barrel length debate AGAIN!

Also, I keep hearing about "potentially messing up a shooter." If I sent it to GAP for the cutting/crowning/threading, I don't see the risk? There is not some magic that goes into cutting a barrel, only precision, unless I am missing something. If the cut job was done by a reputable precision gun shop, than what is the risk?
 
#21
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: ssatt68</div><div class="ubbcode-body">16" would be drastic and may cause malfunction..

The other thing is that suppressor will really heat up your gun </div></div>I agree that 16" is too short. A suppressor will cause some additional retained heat, but this one does have an adjustable gas block so I should be able to tune it so that it doesn't over pressure.
 
#22
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: bm11</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: BCP</div><div class="ubbcode-body">Take it out and shoot it. If it does what you want it to do, fine; if not then worry about having it cut down. GAP AR10's are really nice rifles so I don't think you'll be disappointed. </div></div>This doesn't change the fact that I want to use my suppressor on it. I would be fine threading it, but it seems like if I am going to send it out to thread it, I might as well chop it in the process. Savvy? </div></div>

I understand what you're saying. My point is to get out there and shoot the thing before you spend money on it.

You can always cut it and thread it later on, and if you don't want to then buy a 2nd upper in say 16" and 308 caliber and use that instead.
 
#23
Re: The great barrel length debate AGAIN!

Definitely going to shoot it, I'm not a patient fella and sending out a rifle for 3 weeks before I even try it is not a possibility!
 
#24
Re: The great barrel length debate AGAIN!

You didn't specify who was going to cut and crown. If GAP's gonna do it, have at it. It sounds like your decision was made prior to posting. Plus you considered what you were stirring up prior to posting as evidenced by the title.

I'm not trying to make up for anything with barrel length, I just try to have as effective a tool as possible. Short rifles can and do get the job done, but if there isn't a need for compactness what does the barrel length hurt?

I can suck just as bad with an LTR as I can with a hotrod long tube. I run a 20" 6.5 Creedmoor gasgun and when my head's on straight I shoot it as well as my boltgun, and I am fully aware that what limits my ability right now is lack of dedicated quality training time.


I posted what I did originally (and still stand behind it) because:
a)I troubleshoot for a living and when someone says "cut a GAP barrel" without qualifying who's doing the work I cringe. I already admitted missing the can as motive.
b)the majority of members do not play on two way ranges and getting their rifle in and out of the vehicle involves opening the trunk and carrying a cased rifle to a bench at a square range, not egressing rapidly with a hot weapon.

Frank, not to be contrary, but how many shorties (20" or less) were in the top ten at this year's cup?
 
#25
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">

Frank, not to be contrary, but how many shorties (20" or less) were in the top ten at this year's cup?

</div></div>

I have no idea, and frankly I have no real interest in it... because the Cup like any other competition is just as much a race for "most" of the shooters as it is anything else.

But I can tell you, that when the 6.5CM first hit the block and guys showed up to RO with it, I was called to the tower to be schooled by the new Windcheater against my Valkyrie in 308... well I hit with the first round, the 6.5CM didn't -- not the second round either, nor the 3rd. So honestly what does it have to do with anything ?

I doubt, because of the things written on here, the scare tactics that velocity and barrel length is everything, next to nobody will ever try to compete with a shorter, (less than 20") stick at a SH match.

Look at the Harbinger, in 2005, I spec'd it with a 22" barrel and almost every single person who called GAP wanted a 24" because a 22" was too short. Finally George had to put his foot down that if you changed the barrel length you weren't getting a Harbinger -- meanwhile that year at ASC the Harbinger won the dirty group shot at 600 yards -- against the open field.

Glad you want the numbers on your side, I get it, been that way for ever, but me, if i know the gun is accurate and I have reliable, repeatable data, what does it matter. Results are the same, take a guy chasing numbers versus a guy putting quality time behind his chosen stick and the winner will not be the fastest, flattest shooting one, but the rifle with the best trigger behind it.

Don't get me wrong, dig my 7WSM, but that is a specific tool for a specific job, to race against the crowd, as well right now my AW 1.5 has a 260 barrel on it, but that doesnt' take away from the fact every day I shoot, I usually shoot a 308, and I don't sweat the numbers, I don't sweat the ballistics, I don't even need a dope card, I just know, everything that is happening downrange is me. Unless it's not.
wink.gif
 
#26
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">
.........I just know, everything that is happening downrange is me. Unless it's not.
wink.gif
</div></div>

That does pretty much sum it up.

I just grab the 6.5 or my 7-08 over my 308 because I can be off on my wind call and have a better chance with a better bullet BC wise, all other factors the same.

That's why my advice for BM would be to get an 18" or 20" 308 barrel for the can and some tools and have it all!
 
#27
Re: The great barrel length debate AGAIN!

You see this every where, what did he catch that fish on? He shot a XXX an won thats what I need. Uncle uses XYXY so it must be the best, I want one.

Then there is, if it were real world I'd take,_______ but for match's I only use ______.
Human nature,... chase hardware spec's, never look in the mirror.
 
#28
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">I just grab the 6.5 or my 7-08 over my 308 because I can be off on my wind call and have a better chance with a better bullet BC wise, <span style="font-weight: bold">all other factors the same</span></div></div>

All other factors are never the same...

you guys act like I have no idea the benefits of this stuff, what is ballistically more viable ? Or that I haven't seen it take a Top 10 competition shooter and move him to the win --- that all this is lost on me.

What you don't see, or what I should say everyone ignores is, it doesn't take a 35th place shooter and make him a 10th place shooter, that usually only makes him a 27th place shooter.

Guys can dismiss my debates with Litz over some of the minor things, but really what i am saying is, people read this stuff and think magic will happen, oh sure they qualify it with,<span style="font-style: italic"> "If I do my part" </span> or<span style="font-style: italic"> "all things being equal"</span> but that is exactly my point, they are never equal and very few can count on doing their part as much as the top 10 guys. Maybe 1% of your average shooters can take advantage of this stuff. The variations go well beyond the numbers.

When someone here says they can shoot 1/2 MOA at 100 yards, that doesn't mean they shoot a 1/2 at 200, 400, 600, 800, or 1000... it grows and not in a linear fashion. So a 1/2 MOA shooter, who fights for that .5 MOA group, is lucky to manage 2 MOA at 1000 yards, so the 3/4 MOA advantage they think they are getting, is lost and only works 25% of the time.

We have had matches were 60 shooters given 3 shots at 1000 yards won't have but 2 or 3 shooters connect -- windcheater or not, ballistic advantage or not, it just doesn't work they way. What are the odds of blowing the wind call enough to make a difference and doing <span style="font-style: italic">"everything right, with all things being equal"</span> 1000 to 1 ?

it's why I say, get something you can learn with, practice with and understand better than the next guy. then when you have burned out the barrel, after 10,000 rounds consider the wind cheater, because you are probably close to ready.... but if you haven't burnt out a 308 barrel in the last 2 years, do you think the 6.5CM is going to help put you over the edge into the Top 10 ?

Or that having a 24" 6.5CM is going to slide you into the Top 10 over the guy with the 20" 6.5CM because you have the ballistic advantage ?

To put a period on my rant - 4" and 80fps is not going to make an average shooter more competitive, the only thing that will is proper practice and, believe me when I say, <span style="font-weight: bold">that</span> doesn't care about 4" and 80fps.
 
#29
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body"> it's why I say, get something you can learn with, practice with and understand better than the next guy. then when you have burned out the barrel, after 10,000 rounds consider the wind cheater, because you are probably close to ready.... but if you haven't burnt out a 308 barrel in the last 2 years, do you think the 6.5CM is going to help put you over the edge into the Top 10 ?
</div></div>

I know its getting lost in my typing somewhere, but I'm not arguing the point.
There's a reason I've shot a 308 for 6.5 years before changing......
 
#30
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">You didn't specify who was going to cut and crown. If GAP's gonna do it, have at it. It sounds like your decision was made prior to posting. Plus you considered what you were stirring up prior to posting as evidenced by the title.


</div></div>Fair enough. I didn't have my decision made up though, which is why I asked the question. I am considering just threading the 24" barrel, though based on what Frank is saying, it shouldn't matter. To be honest- I wish it were a .308, and not a .260. I practice a LOT, and the .308 is cheaper to shoot. Furthermore, in Maine, it is rare that I really get to stretch a .308's legs. I only ended up with this .260 because I WANTED A GAP AR-10, and I was ABLE TO MAKE A TRADE FOR IT. I didn't specifically look for a .260, hell, all things equal I would have chosen the .308.

I asked the question because I know the data on .308. My new barrel for my AW will be a 20" (have a 26" now- because that is what the gun came with. I have put 2000 rounds through it in the last 3.5 months, so it will need a new barrel eventually.)

My application of this rifle won't stretch the capability of the caliber. 18" or 26", won't much matter unless I travel somewhere that has a 1300 yard line, in which case I'll probably spin on the 25" 6.5x47 lapua barrel for my AW and shoot that. So truth be told, I really SHOULD have a .260.

The question was posed not because I had my mind made up, but because I need to know. While I made a compromise with a more expensive caliber, I didn't want to then spend 70% more shooting it (factory price of .308 vs .260, both match grade) for NO ballistic advantage.

Really I just wanted to collect some numbers. They are hard to find on this subject (.260 AR-10 muzzle velocity compared to barrel lenth.)

Perhaps the right thing to do is to just sell this thing when it comes in, and pick up a short barreled GAP Ar-10 in the for sale forum. I was just trying to make this one into what I wanted it to be, without throwing away all the benefit of the round, if possible.

I'm kind of going around in circles here, but what I was really looking for is this- 24" will get you what muzzle velocity compared to 22" muzzle velocity compared to 20" muzzle velocity compared to 18" muzzle velocity. If I can make a REASONABLE compromise while chopping it, I think I still might. Or maybe I'll sell it. I dunno.

Thanks,

-Bob
 
#31
Re: The great barrel length debate AGAIN!

I'll bet you could trade that barrel for a GAP AR10 308 barrel.
If you aren't reloading yet 260 is not a really great caliber as far as factory match ammo availability.
 
#32
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">I'll bet you could trade that barrel for a GAP AR10 308 barrel.
If you aren't reloading yet 260 is not a really great caliber as far as factory match ammo availability. </div></div>If you know anyone looking, this one is a K&P stainless with 200 rounds through the upper total. I would gladly trade for a .308.

I am gearing up to reload soon though. I have 1000x123 scenars on order for my 6.5x47, 250 pieces of 6.5x47 lap brass, and the GAP came with 500x140 AMAX's. Going to get around to it one of these days. Winter is coming in Maine, after all.
 
#33
Re: The great barrel length debate AGAIN!

If it's a good barrel you won't lose anymore than 20fps per inch, roughly, which you can reload to compensate for somewhat... I have seen some rifles lose only as little as 7fps per inch, but average, it is about 10 to 15fps per inch.

The 18.5" 260 with an untuned load was about 2685fps, if you look in the SH Rifle build thread Chad has some numbers based off that rifle... which is a bolt gun. I would say, go with 2675fps for an 18.5" and work your way up.

As well the can may add about 10fps on top of your final estimation.

So, for reference sake, let's say a 20" gasser in 260, with a can on it, 2750fps to 2725fps depending on the barrel.

Now go to JBM and run the numbers, so you can see using that swing.
 
#34
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">If it's a good barrel you won't lose anymore than 20fps per inch, roughly, which you can reload to compensate for somewhat... I have seen some rifles lose only as little as 7fps per inch, but average, it is about 10 to 15fps per inch.

The 18.5" 260 with an untuned load was about 2685fps, if you look in the SH Rifle build thread Chad has some numbers based off that rifle... which is a bolt gun. I would say, go with 2675fps for an 18.5" and work your way up.

As well the can may add about 10fps on top of your final estimation.

So, for reference sake, let's say a 20" gasser in 260, with a can on it, 2750fps to 2725fps depending on the barrel.

Now go to JBM and run the numbers, so you can see using that swing. </div></div>Those numbers I can deal with. I found a thread on some other forum where a guy was only getting like 2550 out of his DPMS LR-260 with an 18" barrel. I wouldn't be cool with that. 2750 I would be all over.
 
#35
Re: The great barrel length debate AGAIN!

If it is a stock barrel, I would suspect it too be low, but if it is a custom barrel it should be higher.

I get more fps out of an 18" 308... so that seems very low to me. But stranger things can and will happen.

Stick to 20" and call it a day. If you didn't want to get a baseline first then you have to risk it.
 
#36
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Lowlight</div><div class="ubbcode-body">If it is a stock barrel, I would suspect it too be low, but if it is a custom barrel it should be higher.

I get more fps out of an 18" 308... so that seems very low to me. But stranger things can and will happen.

Stick to 20" and call it a day. If you didn't want to get a baseline first then you have to risk it.

</div></div>Might buy a chrono before I send it to GAP. They have to keep it for 3 weeks or so anyhow, and I want to get some trigger time in before I give it up. 20" seems like a good compromise between handiness and velocity. It's a K&P stainless barrel, built by George himself, estimated 5 years ago or so.
 
#37
Re: The great barrel length debate AGAIN!

Great thread.
So on avg what does a 308 loose per inch velocity wise? Does the amount lost increase as you get shorter?
I couldnt agree more about training. I teach 17 weapons classes a week. From handgun to LR rifle. People will show up and blame there guns for there faults and think I'm good because of my gun. It's inevitable that I will have to take there gun, make it rock, and give it back to them. People then realize it's themselves that have the most room for improvement, not the gun.
 
#38
Re: The great barrel length debate AGAIN!

Depending on the barrel I'd say no more than 15-20 FPS per inch less. As LL said above some tubes lose as little as 7 FPS/ inch less of barrel.

So in a gas gun with an 18" barrel if you're getting 2460 FPS, then a 20" should be close to 2500 FPS.

Again without getting wrapped around the numbers, the best approach would be to decide at what distance you would like to shoot and spec the barrel length to that distance.

As shown by LL before, he put hits on steel at 800 yards with an 18" barreled bolt gun with I believe was corbon 175s??? I don't know what velocity he was getting out of that 18 and ammo, I really don't care. All I know is he was getting hits perfectly fine at that distance with the barrel and ammo he had regardless of what velocity he might have been getting. That was good enough for me.
 
#40
Re: The great barrel length debate AGAIN!

Have fun with it... Your not getting shot at

I am a broken old SOF guy in a TDA assignment (ROTC)

I just started competitive shooting as an outlet, meet poeple I know I will get along with and have some fun with "the game"

If you are not in the top ten... with out a significant expendature of time effort and money... breaking into the top ten will be vary difficult unless you are SGT York... From what I've seen SGT York would be a middle pack type shooter.
 
#41
Re: The great barrel length debate AGAIN!

Don't be afraid of short. My 16" POF is shooting very good to 650yds and I think it could do well to probably 800yds. With 155 Bergers I am shooting an average of 2530fps with that 16" gun. Dope is dope...I think you are only limited by the range that it goes subsonic. Sure, it takes more mils to get where you are going and you need good field data past 500yds in 50 yd increments but it works.
 
#42
Re: The great barrel length debate AGAIN!

OK,

So here's what I'm thinking now. The rifle hasn't come in yet, when it does, I'm going to shoot it. If I absolutely fall in love with it, I'll have GAP chop it to 20", thread it for my can, and keep it. If not, I'll cash it up and pick up a GAP AR-10 in .308, with an 18" barrel or chop it to 18".
 
#43
Re: The great barrel length debate AGAIN!

I got no quibble anymore with short barrels. LL's has gradually and thoroughly convinced me of their value.

My point is about trying to combine a .260 and a can, especially if you're not a handloader. I don't see much point in taking a Mach 3+ cartridge and running it subsonic.

That's what you'd really be needing to do if you want your can to actually be effective. Without handloading, I don't see how you'd manage it in the first place, and if you could, I seriously doubt a sub-150gr bullet is going to have much terminal energy at subsonic velocities.

Greg
 
#44
Re: The great barrel length debate AGAIN!

You shouldn't have any problem selling a 260 GAP AR-10 if you have to. It really boils down to what you like shooting the most. I tend to be a bit of a traditionalist, so I stick with 308 most of the time when it comes to gas guns.

Incidentally, my long range rig is an APA 18" 308 so I'm absolutely on board with the shorty barrels. Dope is dope, so if you know your gun, you're fine. Does it buck wind like some of the 6.5s? Nope, but I know if the SHTF, I'll always be able to feed that sumbitch.
 
#45
Re: The great barrel length debate AGAIN!

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Greg Langelius *</div><div class="ubbcode-body">I got no quibble anymore with short barrels. LL's has gradually and thoroughly convinced me of their value.

My point is about trying to combine a .260 and a can, especially if you're not a handloader. I don't see much point in taking a Mach 3+ cartridge and running it subsonic.

That's what you'd really be needing to do if you want your can to actually be effective. Without handloading, I don't see how you'd manage it in the first place, and if you could, I seriously doubt a sub-150gr bullet is going to have much terminal energy at subsonic velocities.

Greg </div></div>I'm not trying to be absolutely silent, I have no plans on handloading subsonic ammo. The can is to quit things down, and from what I understand, .260 is quieter than .308 through a .308 can.
 
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