View Full Version : Help me improve my "do-all" carbine
jumbopanda
05-08-11, 01:25
http://i.imgur.com/kUyjL.jpg
When I put together this AR, I wanted something suitable for a carbine course but also good out to maybe 500yd or so with the right ammo. I think it's a decent setup, but couldn't help but look for ways to improve it. Currently it has a KAC URX II rail, which I'm now thinking might be a little heavy, especially when coupled with the Nightforce NXS with Larue mount that I've got on this gun. I don't want a pencil barrel or any other optic, so I guess the only place I can shave weight off of would be the rail. I was looking at the VTAC/Troy Battlerail and thought it might be a good way to trim some weight off of my current setup. The URX II weighs a whopping 20oz, while the 11" Battlerail only weighs 11.2oz. The URX II comes with a built-in front sight (which wobbles a little unfortunately), so I'll take that into account and say that it's worth about 2oz. But even so, the Battlerail would only be 13.2oz. Is there any compelling reason for me to keep the URX II? I also don't like the fact that it requires a special $250 wrench to remove/install, and the QD swivel sockets that don't have an anti-rotation feature. I'm sure there are many other lightweight rail systems out there, so feel free to suggest one if you think it's better than the Battlerail. I'm also open to a regular midlength rail as opposed to a rifle length, since the shorter ones are obviously lighter. I do kinda like being able to grip closer to the front of the gun though.
I've also given some thought to switching to a stainless barrel for greater accuracy. I know it won't matter for close range stuff, but like the title suggests, I want this to be a versatile rifle. I figure that even though stainless is supposed to be less durable than chrome lined barrels, the greater inherent accuracy would make up for this. I mean, even if I do see a noticeable loss in accuracy after 10k rounds, wouldn't it still likely be as good or better than a CL barrel after the same number? Currently I'm shooting on average 1.5-2 MOA from a bench with the BCM BFH barrel, and while this isn't awful, being able to do 1 MOA when I want to would be nice. Being stuck at 1.5-2 kind of takes the fun out of working up my own 77gr "match" loads.
Life of SS depends a lot on how much you heat it up. Generally about half that of chrome lined. 1.5-2 MOA is really good for all purpose but it sounds like you know what you're talking about, SS is the next step.
The URX is a really nice rail and like impossible to take off >.> Rob_S has a chart with rails though! http://spreadsheets.google.com/pub?key=pwswheghNQsFnUZMkZNF2DQ&output=html
Put a carbine stock on in to you can run it short when you want to shoot close. (IMHO)
I really like the 1-4X on top of an accurate AR for a do it all carbine.
When you start thinking about the life of a stainless steel barrel Vs chrome lined think of what the ammo cost is for 5,000 to 8,000 rounds. In particular if you're thinking of shooting match ammo (even if you reload and you take more care with those loads) the cost of a new $400 barrel is a fraction of what you'll pay for ammo.
http://i445.photobucket.com/albums/qq171/kayakcamp/500-600yardtargetA.jpg
Have you looked at the Vltor A5? It would give you more options with your stock length.
bsmith_shoot
05-08-11, 08:06
I think the swap to a Troy rail will make a lot of differance to you. What barrel length are you working with right now? I cant tell from the pic. A SS barrel will make a differance in accuracy at the longer ranges you are talking about, but I will be honest, that barrel you have is more than capable of 1moa if you feed it what it likes, and you do your job. You might wanna look into a differant stock too, but watch out for dropping too much weight in the back, and making it front-heavy.
IDK if this stuff will help, but its all I can think of.
I'd get rid of that scope thing. To me a do all has to have A2 irons. A3 irons in a pinch but the receiver flex on the flat top uppers apparently isn't helped by mounting the carry handle.
The Scopes and Dots are all good gadgets in their specific roles... but Do all? NO WAY.
I'd keep the fixed stock if you're comfortable running it. I run fixed and A5 stocks... with a few carbine stocks that haven't been phased out yet.
The accuracy potential of a barrel has less to do with the material and manufacturing method and more to do with how much attention to detail there was during manufacturing.
1-4s aren't all that great for 500-600 yard shooting...Especially if you have the NP-1 or FC-2 reticles. If you have the mil-dot it should be decent.
A front sight fixed to the barrel and a rear sight with elevation adjustment would also be useful for distance shooting.
Though mentioning them is anathema around here, I have two of Spikes' new SAR rails, and the 9" weighs exactly the same amount as a TRX/VTAC 9" battlerail (9.7oz). I forgot to weigh the 12" before I installed it. I don't know if they have an 11", but if you were to go to a fixed front sight, that probably wouldn't work anyway.
Since you're in California, swapping stocks probably isn't an option? I'm not 100% up on the laws. The A2 isn't all that much heavier than some of the, well, heavier collapsible stocks out there.
jonconsiglio
05-08-11, 13:03
Double post
jonconsiglio
05-08-11, 13:04
The URX II is 3 ounces including the barrel nut and integrated front wight.
If you decide you want a lighter tube style, be sure to add the weight of the barrel nut, front sight and any rail sections you'd need to add.
It's misleading when at first a Tubular rail appears to be lighter than the URX II.
Just want to see you have the facts straight before comparing.
yhmspecter
05-08-11, 14:04
I just changed out a Yhm diamond 9 inch rail for a Troy/VTAC 11 inch battlerail I would say that the battle rail is a good choice.
If you have the funds, buy another light weight upper to drop on. My suggestion would be a 14.5 middy with perm. Battlecomp and MOE rail.
I'm assuming your running some kind of Solar Tactical wrap? I find with these set-ups, the lighter the rifle, the more controllable they are.
My featureless set-ups are as followed (I'm a lefty).
Solar Tactical wrap for a lefty.
I use the top of the safety lever as a thumb rest (this would work for righties running an ambi).
Ambi-mag release
Moe handuards (I have no use for a rail system). I run an off-set light mount off a small piece of rail on top of the MOE. This way it doesn't interfere with my hand placement.
Colt style side sling attachment through the front sight base. I know a lot of people prefer closer to the receiver, but as a lefty, I'm afraid the sling could interfere with ejection.
Quality collapsible stock pinned to my preferred length of pull. I also use the Noveske QD endplate just in case I want to go single point.
Sorry, I didn't really address your rail issue, but from the looks of your pic (and empty rail) you may also not have a need for one.
And my idea of a do anything rifle in CA is my 16" Noveske Middy with MOE, off-set light, TTO comp, pinned adj. stock, RDS, and 3x magnifier with QD (can be removed if not needed)
I'd get rid of that scope thing. To me a do all has to have A2 irons. A3 irons in a pinch but the receiver flex on the flat top uppers apparently isn't helped by mounting the carry handle.
The Scopes and Dots are all good gadgets in their specific roles... but Do all? NO WAY.
I'd keep the fixed stock if you're comfortable running it. I run fixed and A5 stocks... with a few carbine stocks that haven't been phased out yet.
+1 on this. The scope and mount are much heavier than the weight savings you may get by swapping out the URX. Like Markm wrote, a do-all is best with irons. Technology will fail.
Unless you have the wrench, mounting jigs, etc. for the URX handy, it is much less of a hassle to swap uppers and get a light weight barrel with the Troy rail.
If you are getting wobble with the front sight, call KAC and tell them about it. They will sort you out.
jumbopanda
05-08-11, 17:26
+1 on this. The scope and mount are much heavier than the weight savings you may get by swapping out the URX. Like Markm wrote, a do-all is best with irons. Technology will fail.
Unless you have the wrench, mounting jigs, etc. for the URX handy, it is much less of a hassle to swap uppers and get a light weight barrel with the Troy rail.
If you are getting wobble with the front sight, call KAC and tell them about it. They will sort you out.
I like the scope and don't plan on getting rid of it, but I'm curious as to why it'd be worse than irons for longer distances. Sure, it's got a 2 MOA reticle that was designed for CQB rather than a mil dot or something fine, but how would irons be better? As for the scope failing somehow, I do have folding irons on the gun. Not to mention Nightforce scopes have a reputation for being extremely durable.
The front sight wobble is a known issue, and KAC recommends pinching the rail with some pliers to tighten it. Yeah, I was surprised too considering the URX II retails for about $500. :mad: On the plus side, the wobble is front to back, so it shouldn't make a noticeable difference.
I like the scope and don't plan on getting rid of it, but I'm curious as to why it'd be worse than irons for longer distances. Sure, it's got a 2 MOA reticle that was designed for CQB rather than a mil dot or something fine, but how would irons be better? As for the scope failing somehow, I do have folding irons on the gun. Not to mention Nightforce scopes have a reputation for being extremely durable.
The front sight wobble is a known issue, and KAC recommends pinching the rail with some pliers to tighten it. Yeah, I was surprised too considering the URX II retails for about $500. :mad: On the plus side, the wobble is front to back, so it shouldn't make a noticeable difference.
The CQB reticle gives you no way to adjust for the many feet that the projectile will drop at 500 yards, unless you just want to aim a bit high and hope for the best. Neither do your folding irons, unless you've got one of the KAC 600m BUIS thingies.
Proper irons give you the ability to dial in, for example, a 12 minute elevation adjustment for shooting at 600 yards with those 77s.
jumbopanda
05-08-11, 17:41
The CQB reticle gives you no way to adjust for the many feet that the projectile will drop at 500 yards, unless you just want to aim a bit high and hope for the best. Neither do your folding irons, unless you've got one of the KAC 600m BUIS thingies.
Proper irons give you the ability to dial in, for example, a 12 minute elevation adjustment for shooting at 600 yards with those 77s.
Well, the reticle does have some ranging ability:
http://images1.opticsplanet.com/640-640/opplanet-nightforce-compact-nxs-1-4x24-illuminated-riflescope-reticle-fc2.jpg
The distance between the dot and the circle is 5 MOA, the distance between the circle and the tip of the triangle is another 5 MOA, and the distance from the tip of the triangle to the bottom is another 5 MOA. For more precision I could always turn the turrets 9, or 12, or however many MOA a particular load drops at 500yd. The turrets feature an adjustable zero for easy reference.
http://home.comcast.net/~gocartmozart/MK262_trace_report.jpg
And I do have the KAC 2-600M micro BUIS. I wouldn't use anything else simply because the ranging feature works so well. :D
Well, the reticle does have some ranging ability:
The distance between the dot and the circle is 5 MOA, the distance between the circle and the tip of the triangle is another 5 MOA, and the distance from the tip of the triangle to the bottom is another 5 MOA. And for 500yd I could always just dial the scope up ~9.5 MOA.
And I do have the KAC 2-600M micro BUIS. :D
I've shot 600 with circle dot reticles before, it sounds a lot easier than it is.
Good rear, but with a floppy front sight that isn't even attached to the barrel, not the best setup for distance shooting.
Rail-mounted front sights, or rails with sights in them or whatever, are fine for 0-200, you'll probably never notice the difference. But keep in mind that you're aiming the rail, not the barrel, and hoping that the rail is in line with the barrel. At 500-600 yards, especially when you're putting pressure on the rail with a sandbag or bipod or other support, that front sight is moving slightly, but the barrel isn't. This is great when your sighting device is independent of the rail, but not so great when it's integral to the rail. Essentially, free floating is working against you at that point.
jonconsiglio
05-08-11, 17:46
The front sight wobble is a known issue, and KAC recommends pinching the rail with some pliers to tighten it. Yeah, I was surprised too considering the URX II retails for about $500. :mad: On the plus side, the wobble is front to back, so it shouldn't make a noticeable difference.
On one of my SR15's, I started out running it with the front sight flipped up and a T1. It took a bit of an impact and later when I checked to see if it shifted zero, I needed to adjust the rear sight a little kore than 12 clicks if I remember correctly.
This was not the hardest hit either, more like a good bump but directly on the top corner of the front sight. Now, both stay down which isn't my first choice but better than the possibility of knocking them way out of zero.
jumbopanda
05-08-11, 17:52
I've shot 600 with circle dot reticles before, it sounds a lot easier than it is.
Good rear, but with a floppy front sight that isn't even attached to the barrel, not the best setup for distance shooting.
Rail-mounted front sights, or rails with sights in them or whatever, are fine for 0-200, you'll probably never notice the difference. But keep in mind that you're aiming the rail, not the barrel, and hoping that the rail is in line with the barrel. At 500-600 yards, especially when you're putting pressure on the rail with a sandbag or bipod or other support, that front sight is moving slightly, but the barrel isn't. This is great when your sighting device is independent of the rail, but not so great when it's integral to the rail. Essentially, free floating is working against you at that point.
Ah that makes sense. I've never thought about rail mounted vs. barrel mounted front sights before.
But again, I fail to see how irons would be better than the circle dot scope. My eyes are kind of bad, and the scope helps me a lot with being able to see small targets. I don't expect 600yd shooting to be easy by any means, but what's the advantage to irons besides durability?
Ah that makes sense. I've never thought about rail mounted vs. barrel mounted front sights before.
But again, I fail to see how irons would be better than the circle dot scope. My eyes are kind of bad, and the scope helps me a lot with being able to see small targets. I don't expect 600yd shooting to be easy by any means, but what's the advantage to irons besides durability?
I find it easier to shoot with optics vs. irons in 600 yard matches, and I think I do okay with both, but I still am regularly outshot by guys using irons. It's more about consistent placement of the front sight on a large target board than it is about actually seeing or identifying the target. I have an easier time consistently placing a reticle over a magnified view of the target than I do with a standard front sight post that's wider than the target stand itself at 600 yards. Then again, most of the NM sights have thinner FSPs, and I think that helps greatly.
One time I shot a match with an Aimpoint and I did okay. But holdover was more luck than skill. And when the wind changed, I had a hard time dealing with it. Even a little wind will make a big difference at 600, which is why both elevation and windage adjustments (or a reticle designed to allow compensation for such) are really nice, and (IMO) the circle dot reticles become a huge pain in the ass.
If it was my gun, I would replace the barrel with a BCM SS barrel, replace the URX II with a VTAC TRX Extreme with a Troy BUIS, and replace the rifle stock with a Vltor A5 kit with an ACS. So in the end you would have shaved off 3 oz in weight, shifted the balance of the rifle closer to yourself, increased the rifles accuracy, and gotten a BUIS that doesn't wobble. That is my advice, hope it helps.
jumbopanda
05-08-11, 19:34
If it was my gun, I would replace the barrel with a BCM SS barrel, replace the URX II with a VTAC TRX Extreme with a Troy BUIS, and replace the rifle stock with a Vltor A5 kit with an ACS. So in the end you would have shaved off 3 oz in weight, shifted the balance of the rifle closer to yourself, increased the rifles accuracy, and gotten a BUIS that doesn't wobble. That is my advice, hope it helps.
Great minds think alike. :p
I can't get the A5 because I live in California and want to keep my detachable mags. Also I've been looking into the Lothar Walther LW-50 barrels, which is what Larue uses for their Stealth series and OBRs. If anyone knows where I can find a 16" midlength one with ionbond, I'd consider building my own upper with it.
Great minds think alike. :p
I can't get the A5 because I live in California and want to keep my detachable mags. Also I've been looking into the Lothar Walther LW-50 barrels, which is what Larue uses for their Stealth series and OBRs. If anyone knows where I can find a 16" midlength one with ionbond, I'd consider building my own upper with it.
I think you'd be happy with an LW barrel without the Ion Bond. I know I am.
You might contact Little Crow Gunworks to see if they've got the L-W barrel you want. I got my 20" SS L-W barrel from them. They had the best price for that barrel and gave me good customer service
http://www.littlecrowgunworks.com/
I can't get the A5 because I live in California and want to keep my detachable mags.
Sorry man, I feel your pain. I used to live in The People's Republic of California as well.
Nightvisionary
05-09-11, 04:13
Well, the reticle does have some ranging ability:
http://images1.opticsplanet.com/640-640/opplanet-nightforce-compact-nxs-1-4x24-illuminated-riflescope-reticle-fc2.jpg
The distance between the dot and the circle is 5 MOA, the distance between the circle and the tip of the triangle is another 5 MOA, and the distance from the tip of the triangle to the bottom is another 5 MOA. For more precision I could always turn the turrets 9, or 12, or however many MOA a particular load drops at 500yd. The turrets feature an adjustable zero for easy reference.
http://home.comcast.net/~gocartmozart/MK262_trace_report.jpg
And I do have the KAC 2-600M micro BUIS. I wouldn't use anything else simply because the ranging feature works so well. :D
Your ballistics chart is way off. 2830 FPS from a carbine with 77 grain SMK handloads at SAC isn't gonna happen. You will get excessive pressure and blown primers around 2700 or less. Please share your load data because you have surpassed the holy grail of the 75-77 grain club over in the reloading forum.:confused:
jumbopanda
05-09-11, 05:12
Your ballistics chart is way off. 2830 FPS from a carbine with 77 grain SMK handloads at SAC isn't gonna happen. You will get excessive pressure and blown primers around 2700 or less. Please share your load data because you have surpassed the holy grail of the 75-77 grain club over in the reloading forum.:confused:
That's just an example I found online, not exactly what I expect to get out of my 16" barrel. :p
Point is, the amount of drop at 500yd is well within the adjustment capabilities of this scope.
Nightvisionary
05-09-11, 16:09
That's just an example I found online, not exactly what I expect to get out of my 16" barrel. :p
Point is, the amount of drop at 500yd is well within the adjustment capabilities of this scope.
Okay I get ya. You are right as far as what your scope will do. I get 16 moa of drop at 600 with Nosler 77's just under 2600 FPS at 40 degrees so you are right on the money even with a lower velocity.
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