New Colt Retro(s) Soon ... ???

[SteyrAUG]

As I said before, there is no SP1 carbine that would be suitable for a XM177 project other than the early XM177 as they had slickside uppers and 10" barrels. Even in this case, I would not alter a SP1 carbine regardless of its condition if it was all original. I would, however, replace the existing barrel with a 10" A1 profile (pencil profile .625") barrel and save the original barrel. Other than this, I would undertake an XM177 project from a different route. Remember, Colt is just a name brand and nothing more. If you want the Colt rollmarks, start with an 80% lower, have it engraved with the correct rollmarks, mill it out, and have it anodized. You can acquire either a 604 or 603 upper receiver from Nodak Spud and have the NDS rollmark removed when ordering. You can then use the correct profile and length barrel of your choosing.

I'm not worried about exact configurations and if I ended up with something like an "early model" XM177 it wouldn't kill me. I don't have the capacity to do a 80% lower let alone reproduce Colt markings. If I did start with an SP1, what barrel would you recommend? I've never really done a vintage build, I basically just want a decent quality mil spec barrel.

[GRA556]

Already have an original SP1 carbine. Not something I'd cut up or modify.



But again, if I could find a suitable "scratch and dent" candidate that was really no longer collectible but could be salvaged for a XM177 project I'd do that.

I fully agree in developing something in an effort to salvage it. I fully agree with you there. My point is that if you are building a reproduction it doesn't hurt to use as many accurate "contract" pieces as possible and leave the original parts to those looking to repair and/or salvage an original weapon. Similarly I don't believe intaking a pristine SP1 (that collectors are trying to buy whole and as affordable as possible) and parting them out to be sold piece by piece in an effort (or gamble) to get more money out of the original single weapon. Don't get me wrong I believe in spare authentic parts but I just think as many of the original parts as possible for repair and salvage of the original weapons, at least while there is an absent reproduction and quality pieces available.

[SteyrAUG]

I fully agree in developing something in an effort to salvage it. I fully agree with you there. My point is that if you are building a reproduction it doesn't hurt to use as many accurate "contract" pieces as possible and leave the original parts to those looking to repair and/or salvage an original weapon. Similarly I don't believe intaking a pristine SP1 (that collectors are trying to buy whole and as affordable as possible) and parting them out to be sold piece by piece in an effort (or gamble) to get more money out of the original single weapon. Don't get me wrong I believe in spare authentic parts but I just think as many of the original parts as possible for repair and salvage of the original weapons, at least while there is an absent reproduction and quality pieces available.

Trust me, I'd never chop a collectible "anything" and I'd never "part out" a complete original firearm of value. I remember when Colt changed their CAR stocks from aluminum to plastic and a bunch of dealers started swapping out the old aluminum stocks for plastic because they knew the aluminum stocks would sell for a higher price. That kind of crap always drives me crazy.

I even have hesitations when I take an arsenal upgrade M1 Garand and restore it to correct configuration because I know it won't technically be an "original" rifle. Thankfully there is value in "arsenal correct" configuration.

[GRA556]

Trust me, I'd never chop a collectible "anything" and I'd never "part out" a complete original firearm of value. I remember when Colt changed their CAR stocks from aluminum to plastic and a bunch of dealers started swapping out the old aluminum stocks for plastic because they knew the aluminum stocks would sell for a higher price. That kind of crap always drives me crazy.

I even have hesitations when I take an arsenal upgrade M1 Garand and restore it to correct configuration because I know it won't technically be an "original" rifle. Thankfully there is value in "arsenal correct" configuration.

Yes I fully agree.

[Renegade04]

I'm not worried about exact configurations and if I ended up with something like an "early model" XM177 it wouldn't kill me. I don't have the capacity to do a 80% lower let alone reproduce Colt markings. If I did start with an SP1, what barrel would you recommend? I've never really done a vintage build, I basically just want a decent quality mil spec barrel.

The barrel all depends on the route you are going to take. The XM177 and XM177E1 used 10" barrels and the XM177E2 used an 11" barrel. All of these barrels were A1 profile (pencil profile) and had .625" gas port journals. The main issue is whether you are going to go the NFA SBR route or shy away and make it a non-NFA carbine. This will determine whether or not you can use the 11.5" barrel for an XM177E2 or have to go with a 11.75"-12.5" barrel. The moderator you use will decide how long the barrel needs to be in order to achieve the 16" minimum OAL once the moderator (faux) has been pinned and welded.

[SteyrAUG]

The barrel all depends on the route you are going to take. The XM177 and XM177E1 used 10" barrels and the XM177E2 used an 11" barrel. All of these barrels were A1 profile (pencil profile) and had .625" gas port journals. The main issue is whether you are going to go the NFA SBR route or shy away and make it a non-NFA carbine. This will determine whether or not you can use the 11.5" barrel for an XM177E2 or have to go with a 11.75"-12.5" barrel. The moderator you use will decide how long the barrel needs to be in order to achieve the 16" minimum OAL once the moderator (faux) has been pinned and welded.

Looking to do a SBR with a NFA moderator. Looking at this one.

https://www.innovativeindustriesllc....m177-moderator

Not really concerned if I use a 10" or 11" barrel, not making a Title I firearms so no worries there, just looking for a quality barrel that is true mil spec.

[Renegade04]

Looking to do a SBR with a NFA moderator. Looking at this one.

https://www.innovativeindustriesllc....m177-moderator

Not really concerned if I use a 10" or 11" barrel, not making a Title I firearms so no worries there, just looking for a quality barrel that is true mil spec.

Are you wanting to keep it a 1/12 twist like the original XMs had or go with a newer 1/7 twist barrel? Also, are you wanting a barrel assembly (FSB, barrel nut, and Delta ring/flat ring assembly already installed) or a stripped barrel?

[SteyrAUG]

Are you wanting to keep it a 1/12 twist like the original XMs had or go with a newer 1/7 twist barrel? Also, are you wanting a barrel assembly (FSB, barrel nut, and Delta ring/flat ring assembly already installed) or a stripped barrel?

Twist almost doesn't matter, I don't see myself ever firing anything other than .55 gr through it as it will be mostly a novelty rifle. 1/12 is probably closer to authentic anyway. Probably a barrel assembly, I've removed a delta ring to install one piece handguards before but when it comes to removing FSB and things of that nature I'm out of my depth.

[GRA556]

Twist almost doesn't matter, I don't see myself ever firing anything other than .55 gr through it as it will be mostly a novelty rifle. 1/12 is probably closer to authentic anyway. Probably a barrel assembly, I've removed a delta ring to install one piece handguards before but when it comes to removing FSB and things of that nature I'm out of my depth.

In the event another option may be of assistance to you, I'm currently finishing a dissipator build using a DoubleStar dissipator barrel. This barrel has a 1-9" twist. Either later this year or early next year I will do a Colt 605 retro and I will use the best barrel I can find between 1-7" to 1-9" twist. The reason I stay within those parameters is because I can at least utilize the slightly heavier M855 ammo in addition to the XM193 ammo. While a 1-12" twist is authentic it is very limiting and if we go through another era of unpleasantness like we did back in 2012 ammo will become scarce and the faster twist simply affords a wider range of cartridges I can select when things get scarce.

Back last month I finished my SBR XM177E2 retro build. Initially I was going to use a DoubleStar 11.5" barrel assembly using the 1-9" twist. This is the only twist offered by DoubleStar in this configuration but I was satisfied that I could fire more ammo than the XM193 loads and for the same aforementioned reason(s). At the time of purchase I was unaware of any other barrel assemblies offered by other manufacturers.

This changed when I ran across some data that showed the XM193 ammo, when fired thru a 11" / 11.5" barrel, suffers a compromise of it's remarkable and renowned fragmentation after about 49 yards. Of course, some folks out there ask why I'm using an SBR for anything over 50 yards in the first place however this does not mean that I will never have the need to fire at anything critical beyond 50 yards. For this reason I purchased another 11.5" barrel assembly (BCM) that has the 1-7" twist and that is what I completed the build with. Reason for this is while fragmentation, etc., may suffer beyond 50 yards (but should at least be accurate out to 100 yards IMHO), I can also fire the MK262 77 grain rounds and still have the same if not better stopping power at 50 yards and beyond. So when selecting a barrel twist, unless your objective is to be an absolute purist for authenticity (which is fine if that's what you want), you may want to look at the angle of what ammo you can use and what scenarios you may encounter that a heavier projectile beyond the 55 grain XM193 may be required.

You've got the length pretty much selected for an SBR. Now try viewing this from what ammo will determine your twist.

[SteyrAUG]

In the event another option may be of assistance to you, I'm currently finishing a dissipator build using a DoubleStar dissipator barrel. This barrel has a 1-9" twist. Either later this year or early next year I will do a Colt 605 retro and I will use the best barrel I can find between 1-7" to 1-9" twist. The reason I stay within those parameters is because I can at least utilize the slightly heavier M855 ammo in addition to the XM193 ammo. While a 1-12" twist is authentic it is very limiting and if we go through another era of unpleasantness like we did back in 2012 ammo will become scarce and the faster twist simply affords a wider range of cartridges I can select when things get scarce.

Back last month I finished my SBR XM177E2 retro build. Initially I was going to use a DoubleStar 11.5" barrel assembly using the 1-9" twist. This is the only twist offered by DoubleStar in this configuration but I was satisfied that I could fire more ammo than the XM193 loads and for the same aforementioned reason(s). At the time of purchase I was unaware of any other barrel assemblies offered by other manufacturers.

This changed when I ran across some data that showed the XM193 ammo, when fired thru a 11" / 11.5" barrel, suffers a compromise of it's remarkable and renowned fragmentation after about 49 yards. Of course, some folks out there ask why I'm using an SBR for anything over 50 yards in the first place however this does not mean that I will never have the need to fire at anything critical beyond 50 yards. For this reason I purchased another 11.5" barrel assembly (BCM) that has the 1-7" twist and that is what I completed the build with. Reason for this is while fragmentation, etc., may suffer beyond 50 yards (but should at least be accurate out to 100 yards IMHO), I can also fire the MK262 77 grain rounds and still have the same if not better stopping power at 50 yards and beyond. So when selecting a barrel twist, unless your objective is to be an absolute purist for authenticity (which is fine if that's what you want), you may want to look at the angle of what ammo you can use and what scenarios you may encounter that a heavier projectile beyond the 55 grain XM193 may be required.

You've got the length pretty much selected for an SBR. Now try viewing this from what ammo will determine your twist.

In an ammo shortage I won't be shooting my 177 replica any way and can't see shooting anything more expensive than 55 grain. Also faster twist means shorter barrel life so no reason to do that for a novelty firearm.