What caliber for GAP-10?

T

taseal

Gunny Sergeant
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Apr 18, 2011
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#1
I know the caliber thing comes up very often here...

I want a .308 for few reasons -

<ul style="list-style-type: disc">[*]Easy to find quality match ammo[*]I can get FGMM 168 SMK ammo for 20 bucks. that's dollar per round for match ammo... that's a huge plus for training[*]I can use the bullets on my .30-06 if need be (168 amax)[*]Popular LE/MIL cartridge (Might use it myself one day)[/list]

and I want .260 or 6.5CM for few reasons as well
<ul style="list-style-type: disc">[*]Shoots like a fricking laser beam. Especially at longer distances [/list]

When you decided to get your GAP-10 (or any semi for that matter) what made you decide what caliber you wanted to go with? barrel life? distance you'd be shooting? Lethality?

I have a custom .30-06 which is my 'mile gun' and setup for 1000 yard and more shooting. This rifle will fill a dual role of close in (any semi should be able to do close in in my opinion) and upto 1000.

I do reload, but I don't enjoy it. I only do it, because there aren't that many setups for my bolt gun for it's intended use. and the chamber is cut specific to a COAL that I have setup for 208 amax... I would rather buy match ammo for a .308 then to have to load few hundred rounds on a single stage press.

Just FYI, the closest 'long distance' range is being built right now and is 500 yards... and that's 2 hours away. the closest 1000 mile range is 4 hours away. That's something else to keep in mind. and like I said, I might have to use this rifle in LE in the future. small possibility, but it's something I'd like to think about.

Thanks!

ps. I put a poll in just to see rough numbers. (I will also be researching this matter after I post this here)

edit - Found another thread, which helped, but it was more of ppl just inputting what they use. not really practical for my questions
 
#2
Re: What caliber for GAP-10?

There's no AR rifle based on the .308 cartridge that is worth it's salt at both 1000 or CQB.

Gaff off the .260

Enjoy the pain of picking one over the other and I would add the 6mm Creedmoor. GAP knows how to set you up for that doozy. Barrel life will probably be on par with the .260 which isn't good.

EDIT: Best to you. AR-10 class rifles are another world of fun.

EDIT II: The 6.5CM would not be a wrong answer.

 
#3
Re: What caliber for GAP-10?

Me personally... If you're not going to use it to compete with, there's no reason to not go .308 for it. The training aspect you get from shooting .308 with calling wind, ranging, increased barrel life, and ammunition availability/cost outweighs the benefits of the flatter shooting rounds.

If you're going to compete with it and want to be highly competitive, go 6/6.5mm.

Intended purpose is everything.
 
#4
Re: What caliber for GAP-10?

6.5 Creedmoor because it feeds well from an AR magazine. Less recoil than a 308win and better ballistics for target shooting and competition. Factory 140gr amax loads aren't too expensive, and they are consistent.
 
#5
Re: What caliber for GAP-10?

What kind of lethality is to be expected from 6.5cm?

Also how does that compare to 260? Assume it's just a flat?

I'd love to compete with it when the time comes
 
#6
Re: What caliber for GAP-10?

Work gun = .308

This is kind of different, but I run a short bolt gun. It's set up for suppressor and it's a 308. Because I use it for work I chose 308 but have shot in a few comps with it and still placed in the top 1/3. I would have placed in the top 10 if it wasn't for MY shooting abilities, or lack there of. I voted stick with 308 but a 6.5/260 is fun
smile.gif
 
#9
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: taseal</div><div class="ubbcode-body">What kind of lethality is to be expected from 6.5cm?

Also how does that compare to 260? Assume it's just a flat?

I'd love to compete with it when the time comes </div></div>

Think of the 6.5 Creedmoor as a slightly shorter .260 case with the shoulder pushed forward to 30 *. Let's you seat the longer higher BC bullets out a little more while still maintaining mag length constraints. Performance will mimic a .260 in a bolt, and more than likely slightly edge out .260 in a semi, because of above mag constraints and case design.

Personally I think this is the better 6.5 flavor for a semi.

Barrel life of a .260 isn't bad unless you're comparing to a .308. There are several folks around with over 3K on their .260's still shooting well. A barrel is a consumable item to me. When it craps out, get another one. Hopefully it'll give you a little warning.


If I cared about barrel life I sure wouldn't have picked the 6 Creedmoor (6.5 necked down) 105's at just below 3100 and 115 DTAC's in the high 2900's. That's going to be a 2K ish barrel life if I don't hammer it. I'll just have George and crew make me another tube for it.

If you have the funds you could do like I did. Get a POF P308 in either a 16.5" or 20" 308 config and have GAP build you a 6.5 or 6 Creedmoor upper.
 
#11
Re: What caliber for GAP-10?

I am pondering the same calibers as well. After going to a long range shoot and seeing the 6.5CM perform and what it sounds like when suppressed I am going to build a AR10 platform in this caliber. The match grade factory ammo isnt more more than a 308. I also have 3 other 308 rifles and wanted something different that wasnt effected by the wind at longer ranges. I am getting 308 match for 22 a box in a 168 SMK. Check this site out as well really like how its broke down so you can compare anything you want. Hope this helps a lil. http://ammoseek.com/?gun=rifle&cal=255&grains=0&mfg=&keywords=&sortby=cpr
 
#12
Re: What caliber for GAP-10?

One lower, two uppers. That's what I did. I can shoot the piss out of my 308 upper and then put on the 6cm for comps or varmints an the gun will feel the same.
 
#15
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: taseal</div><div class="ubbcode-body">What's the cost of an upper for a GAP-10? I'm assuming about 2,000 considering the POF is upper is around 500 bucks...</div></div>

Where are you finding a POF upper for $500? You can get a lower for that price but there isn't a chance in hell of getting a POF upper for that.
 
#17
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: KillShot</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: taseal</div><div class="ubbcode-body">What's the cost of an upper for a GAP-10? I'm assuming about 2,000 considering the POF is upper is around 500 bucks...</div></div>

Where are you finding a POF upper for $500? You can get a lower for that price but there isn't a chance in hell of getting a POF upper for that. </div></div>

I meant lower... lol if I assume gap upper is 2,000. that would make the POF lower 500
wink.gif
 
#18
Re: What caliber for GAP-10?

How bout a 300 SAUM with adjustable gas block and armalite length gas system. I think you could get the 300 SAUM to match your 30-06 ballistics while using the same projectile. That would be cool if you could use the same DOPE and wind calls. I just carry a lighter weight AR with 77gr smk and a biathlon sling for my bolt gun, best of both worlds.
 
#20
Re: What caliber for GAP-10?

Maybe its just the reloading book I'm looking at but the .260 doesn't look like it beats the .308 anywhere. The book also doesn't have the 6.5 creedmore in it. It shows the .260 running about 175 more fps but almost the exact same drop @ 600 yards. This was comparing 175 gr to 130 gr also.
 
#21
Re: What caliber for GAP-10?

I think your book is wrong. 6.5 CM & .260 are almost identical. I have a GAP-10 20" barrel in 6.5 CM that is at 2733fps with the Hornady 140 grain amax. I am at 6.9 mils at 900 yards. The .308 is not going to be close.
 
#23
Re: What caliber for GAP-10?

That is with factory ammo. I have to admit I was really surprised. I have tested it on two separate occasions and get the same number. I am using the new magneto speed chrono.
 
#27
Re: What caliber for GAP-10?

Where is there a 500yd range being built in South Florida? I'm assuming the 1000yd range you're talking about is manatee. I'm heading there this weekend.

I don't have any experience with the 6.5/260 but I do have 2 .308s. If you don't own a .308 id get that.

That said, my next bolt gun or possibly ar-10 will be something 6.5 caliber just not sure which one yet.
 
#28
Re: What caliber for GAP-10?

If you want to shoot a lot and aren't going for little groups but just love to blast, I would go .308 as you can get relatively inexpensive ammo. Otherwise I'd go with 6.5 CM as it seems to be an amazing caliber and the match grade factory ammo is close in price.
 
#29
Re: What caliber for GAP-10?

If there's a realistic possibility of it being used for LE purposes, you should be going with .308. There are significant number of high quality duty .308 loads, and you can use what you need to meet your needs since there is a selection for every type of shooting situation you'd likely encounter, from barriers to urban crowds. There are some "duty capable" .260 Rem loads out there, but not dedicated duty rounds from what I can locate. The .260/6.5mm may be flatter shooting, but the .308 will carry a lot more energy with the heavier weight. If you've ever shot into a vehicle, you know how difficult it is to make a good hit on a target inside. Cars are unique barriers, and they're something that we deal with on a regular basis. If I have to punch through a car door, I'd rather be doing so with a 165gr .308 barrier load than a 139gr .260/6.5mm hunting load.
The mission drives the gear.

Just my thoughts on the matter. YMMV
 
#31
Re: What caliber for GAP-10?

I have this dilemma as well..

I currently shoot .308 175 CC Nosler @ 2610Fps and have a drop of 30.8 MOA at 1k

From talking to Nosler and calculating the ballistics a 140gr CC Nosler @ 2750Fps would only gain me 4 MOA at 1k

... or am I doing the math wrong. 4 MOA is nice, but not sure if its worth setting up the press for a new caliber and the new brass, etc.

Also while the 6.5 has a better BC, wouldn't a smaller bullet not buck the wind as well ?

Still learning the details....
Thanks
 
#33
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kritos666</div><div class="ubbcode-body">
I currently shoot .308 175 CC Nosler @ 2610Fps and have a drop of 30.8 MOA at 1k
</div></div>
you sure you don't mean 38 MOA...JBM has it 40 MOA but that is a computer. If you could get a 308 to a 1000 with 30 MOA I wouldn't need a 260.
 
#34
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JSTARSZ</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kritos666</div><div class="ubbcode-body">
I currently shoot .308 175 CC Nosler @ 2610Fps and have a drop of 30.8 MOA at 1k
</div></div>
you sure you don't mean 38 MOA...JBM has it 40 MOA but that is a computer. If you could get a 308 to a 1000 with 30 MOA I wouldn't need a 260. </div></div>

yup 2 weekends ago (when I read the wind right 3-9MPH full value (kept changing on me)
30.8 MOA was the correction in elevation(I just double checked). I was shooting at a 30" silhouette at 1k. I can give you all the atmospheric conditions if you like. I haven't been shooting since, so they are still in the calculator.

That said, I take it your saying ... don't bother /w 260 and be happy with the performance I'm getting from my 308?
 
#35
Re: What caliber for GAP-10?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kritos666</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: JSTARSZ</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kritos666</div><div class="ubbcode-body">
I currently shoot .308 175 CC Nosler @ 2610Fps and have a drop of 30.8 MOA at 1k
</div></div>
you sure you don't mean 38 MOA...JBM has it 40 MOA but that is a computer. If you could get a 308 to a 1000 with 30 MOA I wouldn't need a 260. </div></div>

yup 2 weekends ago (when I read the wind right 3-9MPH full value (kept changing on me)
30.8 MOA was the correction in elevation(I just double checked). I was shooting at a 30" silhouette at 1k. I can give you all the atmospheric conditions if you like. I haven't been shooting since, so they are still in the calculator.

That said, I take it your saying ... don't bother /w 260 and be happy with the performance I'm getting from my 308? </div></div> If I had a 308 that would shoot 30 MOA at a 1000 I wouldn't need anything else because that is some pretty flat shooting. According to JBM you would have to send the 308 at 2900 fps to get to 30 MOA or at 2610 you would have to be at some serious elevation to get to that MOA. From JBM using 2610 at 1500 altitude:
Range Drop Velocity
(yd) (MOA) (ft/s)
0 *** 2615.9
100 0 2441.7
200 -1.8 2274.2
300 -4.6 2113.7
400 -7.8 1959.9
500 -11.5 1811.9
600 -15.6 1669.2
700 -20.3 1531.4
800 -25.6 1398.9
900 -31.6 1272.5
1000 -38.4 1154
 
#36
Re: What caliber for GAP-10?

This is the dope I used and I hit the target several times. I'm not claiming anything, I'm just trying to learn more and passing along what works for me and what doesn't.

-- Cartrige
2610Fps
175 CC noslers (.505) BC

-- atmosphere
3mph wind (but wind did vary from 3-9 MPH)
74.0F
25.66 Baro
28% humid
4178 alt.


(taken from BulletFlight-M)
yards - (elevation) | (wind)
100 - .1 MOA | -0.1 MOA
200 - -1.7 MOA | -0.1 MOA
300 - -4.2 MOA | -0.1 MOA
400 - -7.1 MOA | -0.2 MOA
500 - -10.3 MOA | -0.2 MOA
600 - -13.7 MOA | -0.3 MOA
700 - -17.4 MOA | -0.3 MOA
800 - -21.5 MOA | -0.3 MOA
900 - -26.0 MOA | -0.4 MOA
1000 - -30.8 MOA | -0.4 MOA
 
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