Hey guys I've been wanting to do an Spr type build for a long time but my funds are a bit limited. I have a Sig 556r that I do love though. Being that I've seen it's pretty accurate with irons, what's your opinion on making it into an spr platform?
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Sig 556R Gen 2 as an SPR
- Thread starter BlackJack223
- Start date
The 556R is a fun rifle to shoot, but to get it up to optimal shooting level is still going to run you a bit! The swiss stock needs to be swapped out and depending on how you go it can be anywhere from $200-300 bucks. Since there is only 1 company who makes an adapter for it. Then there's the plastic forend that IMO needs to be swapped out for something more stable. In all with both your looking at around $400-500 before even looking at optics...
Thanks for the info and reply smokin. I do agree with you there, I do have a little bit of a head start since I have the swat version that has the quad rail instead of that cheap hand guard. I know it would take a little change to make it right but I guess my question is, "is the x39 round up to the challenge" or is it more of a wasted effort do you think?
Are you looking more at looks, or performance.
If performance, what kind of performance? When I look at "SPR's", I generally am looking for a gun that will hit IPSC silhouettes or 18" plates at 600yds, spitting 75gr and 77gr BTHP's.
Where I'm coming from in this topic is a schedule where I run Designated Marksmen courses throughout the year, which is something very near and dear to me. I think the average all-round set-up is a free-floated AR15 with a quality barrel chambered in .223 Wylde if we are staying with the 5.56 cartridge, otherwise the 6.5 Grendel kills it.
For out West, an 18" gun might make sense for those who are over 6ft tall. For East of the Mississippi, I'd be happy with a 12.5" gun much of the time, unless looking at terrain near and in the Appalachians, at which time I would want some more reach, but still would want a lightweight carbine so I'm not smoked after a yomp up the trail.
In Europe, most areas are fine with an 11.5" carbine with a quality barrel, free-floated, suppressed with a short can.
Biggest factors in selecting an SPR carbine are fitting the gun to the shooter, the geographic region you live in, and the accuracy requirements you have based on the targets in your area. For me, that usually means a 1.5 MOA capable blaster is totally fine, since we only shoot out to 600yds on 18" plates.
The Sig would probably cut the mustard out to 400yds at least, but I don't know how yours shoots. If it has any forward weight to it that throws off the balance, I would look at a standard DI AR15 and balance it out to you.
If performance, what kind of performance? When I look at "SPR's", I generally am looking for a gun that will hit IPSC silhouettes or 18" plates at 600yds, spitting 75gr and 77gr BTHP's.
Where I'm coming from in this topic is a schedule where I run Designated Marksmen courses throughout the year, which is something very near and dear to me. I think the average all-round set-up is a free-floated AR15 with a quality barrel chambered in .223 Wylde if we are staying with the 5.56 cartridge, otherwise the 6.5 Grendel kills it.
For out West, an 18" gun might make sense for those who are over 6ft tall. For East of the Mississippi, I'd be happy with a 12.5" gun much of the time, unless looking at terrain near and in the Appalachians, at which time I would want some more reach, but still would want a lightweight carbine so I'm not smoked after a yomp up the trail.
In Europe, most areas are fine with an 11.5" carbine with a quality barrel, free-floated, suppressed with a short can.
Biggest factors in selecting an SPR carbine are fitting the gun to the shooter, the geographic region you live in, and the accuracy requirements you have based on the targets in your area. For me, that usually means a 1.5 MOA capable blaster is totally fine, since we only shoot out to 600yds on 18" plates.
The Sig would probably cut the mustard out to 400yds at least, but I don't know how yours shoots. If it has any forward weight to it that throws off the balance, I would look at a standard DI AR15 and balance it out to you.
If you are just plinking around then stick a scope on top of it and have fun. A 1-4 would be great. If you want actual performance then the AK round sucks for that, 223 is much better.
I would like a combination of both to 've honest! While I think the rifles look amazing I'm also starting to shoot longer distances (around 400 is about as far as I've gone) I live in the Charleston area of sc so chances of me making a shot past 200 in the woods is situational at best and the exception. But to really answer your question LRR the DM has always been a topic of interest to me! I've seen a few of the mil-spec does that come through my unit from time to time and I actually wanted to build a sort of no. 12 clone but I just didn't have the money. But I do have that Sig lying around 
even if it is kind of a moot point I'd still like to ask what would make up a good 5.56 spr? But back on subject the more realistic question was the capability of the x39 to accurately make ~400 yard shots since I don't have to much experience with the round.
even if it is kind of a moot point I'd still like to ask what would make up a good 5.56 spr? But back on subject the more realistic question was the capability of the x39 to accurately make ~400 yard shots since I don't have to much experience with the round.Back in the days when AK kits were cheap and plentiful we built AKs with scout scopes that would easily do that. With hand loaded ammo, of course.
I think Hornady makes 7.62x39 ammo with steel cases but good bullets. I have not tried them myself but I would not expect to be too disappointed with the results considering the quality of their ammo in general.
I haven't messed with the higher quality ammo too much alpine, what kind of groupings have you experienced with say hornady or other brands you might have tested?
I would like a combination of both to 've honest! While I think the rifles look amazing I'm also starting to shoot longer distances (around 400 is about as far as I've gone) I live in the Charleston area of sc so chances of me making a shot past 200 in the woods is situational at best and the exception. But to really answer your question LRR the DM has always been a topic of interest to me! I've seen a few of the mil-spec does that come through my unit from time to time and I actually wanted to build a sort of no. 12 clone but I just didn't have the money. But I do have that Sig lying around
I'd leave the sig alone and start slowly building a free-floated 223 AR 'spr'. Start with basics like get a good deal on a barrel (white oak 18" rifle gas), an upper, lower, etc. A few months from now, maybe november-december, you'll suddenly have both instead of wasting money trying to turn one into the other.
Just to expand on cartridges a little more:
There is nothing inherently wrong with the com bloc calibers 7.62x39mm and 5.45x39mm. The disappointments in the accuracy department come from the way they slap the guns and the ammo together.
Granted, the Russians overdid the case taper a little when they modeled the 7.62x39mm after the German 7.92mm kurz (introduced with the StG44 towards the end of WWII). But with a little attention to the details you can make this round shoot just as well as anything else in this class.
The 5.45x39mm is wickedly accurate if you pull the steel core bulllets, reweigh the powder and put something like a resized Berger 70 VLD or Barnes 69 Match Burner in the steel cases. If someone would make brass cases for the 5.45x39mm I would prefer that caliber over the 5.56 hands down. Magnified in Photoshop, a 5.45x39mm cartridge looks very close to the modern designs like 6.5 Creedmore (except for the shoulder angle). Relatively short case and plenty of room in the magazine for long, slender bullets. Were it not for NATO, few people would bother with the 5.56.
There is nothing inherently wrong with the com bloc calibers 7.62x39mm and 5.45x39mm. The disappointments in the accuracy department come from the way they slap the guns and the ammo together.
Granted, the Russians overdid the case taper a little when they modeled the 7.62x39mm after the German 7.92mm kurz (introduced with the StG44 towards the end of WWII). But with a little attention to the details you can make this round shoot just as well as anything else in this class.
The 5.45x39mm is wickedly accurate if you pull the steel core bulllets, reweigh the powder and put something like a resized Berger 70 VLD or Barnes 69 Match Burner in the steel cases. If someone would make brass cases for the 5.45x39mm I would prefer that caliber over the 5.56 hands down. Magnified in Photoshop, a 5.45x39mm cartridge looks very close to the modern designs like 6.5 Creedmore (except for the shoulder angle). Relatively short case and plenty of room in the magazine for long, slender bullets. Were it not for NATO, few people would bother with the 5.56.
You mean high power style? Like standing straight up, in a "straight jacket", AR 15 mounted like an RPG, with half an eternity to send bullets towards barn door sized targets from bull barrels with pimped-up aperture sights and then bragging about the number of x's. Somehow, this looks like either having chosen the wrong tool for the job or the wrong discipline. This is the sentiment of someone who shot 10 meter air rifle competitively as a youngster.
I recently bought a slightly used barrel from a "service rifle" shooter to put it in my 3Gun rifle - after shaving several pounds off it on my lathe. Originally it had a 1.00 diameter all the way to a rifle gas block. Who exactly is "serving" with a pig like this? To call these rigs "service rifle" is a joke and IMO also an insult to those who have to defend their lives with the real deal. Either grab an "as issued" gun from the rack and show what you got under time pressure in an honest service rifle competition or compete in the Olympics with the appropriate hardware but not half of this and half of that. [End of rant]
The modern "assault rifles" were designed to engage multiple humanoid targets fast (!) at medium distances. With a little care (but not excesses that make them impractical for combat use) a Sig556R will do that just as well as any "normal" AR15 . I thinks that is what the OP was after.
In terms of external ballistics the 7.62x39mm is obviously at a disadvantage because of longer flight time (more wind drift). However, the terminal ballistic prize goes clearly to the heavier 7.62 bullet. For shooting at meat inside of 500 I would chose the latter. While managing a hunting area in Germany I shot over 100 deer with a .223 Rem, tipped with high end hunting bullets and the results were sketchy. Everything ended up at the butcher but some ran quite a bit. Here I use a 300AAC (supersonic Barnes TacTX) during the white tail rifle season and that is just the cat's meow in comparison. No fuss, no muss, just meat in the freezer. Keep in mind that a white tail is a bit sturdier than the European roe deer. Since the same bullets could be pushed a little bit faster in the 7.62x39mm case, the results should be no worse. If it were not for NATO, the .223 would be mostly a mid range varmint cartridge.
Don't get me wrong, I love the 5.56 for gun games and load it in batches of 1000. It is just the blind fan-boyism about the US military stuff that sometimes get me wound up. Why did the AMU experiment with what finally became the 6.8SPC? Why did SOCOM cancel the SCAR16 contracts and keeps ordering the SCAR17? For the sake of those who serve in the armpits of the world I hope they are going to kick the 5.56 to the curb sooner than later. But unfortunately, the successor may just be a caseless 4mm-ish mini-mouse cartridge because of concerns that the average grunt might be too recoil sensitive for anything that puts some serious hurt downrange. Funny, my friends who were running and gunning for their lives do not recall to be very sensitive to pain (let alone the "recoil" of a mouse gun) when their Adrenaline was off the charts.
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And this is really what I meant to be honest. I'm not looking to punch a ragged hole at 400 yards, hell I'm probably not good enough of a shooter to do it consistently, building a quality ar is an expensive venture and emts don't make good money
my main reason for this thread was whether or not the round and platform that I have available would serve the purpose I have in mind. I want it to be accurate enough to be able to hit the black at that range or at least close enough so that I'll be making lethal hits on target. If the x39 with the Sig is capable of that then that's what I'll 've usuong happily! It really is a quality weaponAnd this is really what I meant to be honest. I'm not looking to punch a ragged hole at 400 yards, hell I'm probably not good enough of a shooter to do it consistently, building a quality ar is an expensive venture and emts don't make good money
Put a scope on the SIG556R and have someone make you some good ammo (or try the Hornady offerings). See were this goes. If you can shoot the gun safely and solidly without the handguard, try that and see whether it makes a meaningful difference. If it does, upgrade the handguard, otherwise leave it alone.
I comparison, borrow a friend's AR15 and see how you like that. My guess is that sooner or later you will have an AR anyway. Not because the SIG556R cannot get the job done but because the AR15 is to guys what the Barbie doll is to little girls. Easy to dress up and easy to change around. Sometimes I think they even multiply at night.
BTW: What region of the country do you live in?
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I live in the south east. The Charleston area of South Carolina. And I know what you mean with the AR, all of my quals were done with an m4 and irons. I do like the ar platform and it's a great gun but sand and dirt don't really agree with it if you know what I mean. That was actually one of the reasons I bought the Sig (great reliability and I just love the .30)
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The far rifle is a 556R with SWAT hand guards and an ACOG TA-11 ( front is a 556 SWAT/ .223). It will group the Wolf ammo around 2" @ 100 yards. Ammo quality hurts the 7.62X39 accuracy potential . Lapua ammo it the best to feed it but I shot the last of mine up years ago and its damn expensive to find today if you can. The SIG 556R is a nice platform for the AK caliber that fits most adults and is comfortable to shoot with good ergonomics , sight options and trigger.
Very nice rifles cal, how much did that acog run ya? I've thought about throwing a magpul ubr on mine just because I need a little more LOP. Has the ACOG served you pretty well on there?
I can't remember the exact amount but around a grand for the TA-11. Its larger than the other ACOG's but its the only one I like the eye relief on. It has the red horseshoe reticle which works great for me.
The ACOG is a rugged field / battle sight with enough magnification for the range of the rifle mounted to. Generous eye relief and a good field of view and the only down side is the cost.
I like the Swiss folder on the 556R and have an ACE folder on the .223 SWAT 556.
I agree, the Swiss folder is a nice stock and it wouldn't be to bad if my nose wasn't almost touching the rear diopter sight I have on there XD
https://www.trijicon.com/na_en/products/product3.php?pid=TA55A I've been looking at one of those maybe if I can find a decent used one. I'd like to look at some leupolds but I haven't had time to browse the selection yet.
Well if you want to stick with it buy what makes you happy.
Personally I learned long ago not to try and make a rifle into something it's not. The rifle always wins. The money that you spend on an ACOG and a UBR stock would build you a decent AR that will do what you are asking, then you'll have the sig which is a great carbine and the AR which would be a little more towards a target/varmint rifle. If you want an optic I think the 300 blackout reticules that subtend supersonic loads match up with the AK round there are a few of those out there. That would be the most useful IMHO.
Personally I learned long ago not to try and make a rifle into something it's not. The rifle always wins. The money that you spend on an ACOG and a UBR stock would build you a decent AR that will do what you are asking, then you'll have the sig which is a great carbine and the AR which would be a little more towards a target/varmint rifle. If you want an optic I think the 300 blackout reticules that subtend supersonic loads match up with the AK round there are a few of those out there. That would be the most useful IMHO.
There is nothing wrong with buying a quality optic that can be used on multiple platforms. The ACOG is not a long range sight IMHO and a quality variable would be more versatile if you do not want or need the ACOG features.
As to the 556R platform, I like the penetration of the 7.62X39 cartridge and the SIG 556R is the 1st platform with the ergonomics that fit an adult , gas piston operation with good trigger and rails for multiple sight or optic attachment options. Since I had a 556 adding the 556R gives me the exact same handling characteristics in two calibers. I sold an Arsenal AK for my 556R and have zero regrets. The AK was minute of car window accurate and my 556R can make head shots easily at 100 yards. If I get some ammo that groups well I would like to stretch it out.
I would not dump a ton of money into it other than sights / optics and a stock that fits you better is fine as well. The basic configuration is great for what it is.
As to the 556R platform, I like the penetration of the 7.62X39 cartridge and the SIG 556R is the 1st platform with the ergonomics that fit an adult , gas piston operation with good trigger and rails for multiple sight or optic attachment options. Since I had a 556 adding the 556R gives me the exact same handling characteristics in two calibers. I sold an Arsenal AK for my 556R and have zero regrets. The AK was minute of car window accurate and my 556R can make head shots easily at 100 yards. If I get some ammo that groups well I would like to stretch it out.
I would not dump a ton of money into it other than sights / optics and a stock that fits you better is fine as well. The basic configuration is great for what it is.
BCG what would you recommend as a lower/upper for said platform?
Cal, I'm of the same mindset, the reason I looked at an acog was for the durability. Did you have any other suggestions for optics?
Cal, I'm of the same mindset, the reason I looked at an acog was for the durability. Did you have any other suggestions for optics?
For me I've been debating the trigger upgrade for a while now... to me it's a bit sloppy and heavy. Considering most of the rifles I have are between 2.5-3 lbs. It is fun ringing steel at 565 yards though.
Optics comes down to intended use, personal choice and what your wallet can afford. Any quality scope or red dot should work well.
If anyone has a SIG and not adjusted the trigger you can really improve the trigger in about 10 minutes. Its easy to adjust and much improved.
The key parts are in-spec upper and lower receiver, good barrel, good trigger, free floating handguard. I like aero precision uppers/lowers, white oak barrels and giessele triggers. If you want to buy something ready made I have heard good things about the Colt-branded 'marksman' or whatever rifles and the DPMS MK12/SASS setups, RRA stainless barreled ones like the ATH are good shooters too. Elferster had a big thread with his ATH RRA and it was shooting very well.
For an in-spec SPR type rifle like the 'boys' have overseas you'll need to spend out the ass, like ~2000 bucks.
For an in-spec SPR type rifle like the 'boys' have overseas you'll need to spend out the ass, like ~2000 bucks.
I know what you mean man, it works fairly well for me though, how's the magazine work with the mag in by the way? I've always thought it would be to tall for the bipod
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