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Posted: 6/8/2011 6:04:10 PM EDT
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My SP 1 doesn't shoot to its potential and I need some help. The best I can get it to do is about 6-7 inches at 100 yards. Early 80s gun, all original, near pristine condition, less than 200 rounds down the tube. 16" barrel, including the flash suppressor. Shorty stock. Barrel and chamber are perfect, crown is perfect, headspace is fine, fired brass looks good with no pressure signs or irregularities in the chamber. Sights are original, obviously not target sights, but good enough to shoot a group. Trigger sucks but shooting off the bench it shouldn't make a huge difference. Bullet impacts are scattered, not vertical stringing. Shooting 55 grain soft points, Remington factory ammo. Tried Wolf 55 grain also, as well as a couple of different handloads, 55 grain ballistic tips, and 45 grain soft points. The twist is 1-12, and should stablize bullets of those weights OK. Holes in the paper are clean cuts, no tumbling. I haven't tried anything heavier than 55 grains or lighter than 45. Everything on the gun is tight, clean, and functioning properly. I've shot it off the bench rested on the handguard, rested on the barrel, rested front and rear, prone, offhand, shooting off the magazine, and shooting off the magazine well without a magazine in the gun. Still get 6-7 inches. Tried it at 50 yards and it will do about 4 inches.
The same loads shoot through my other guns, so I know it's not the ammo. I can pick up another AR right after this one and shoot two inches at 100 without any trouble, so while my eyes aren't what they once were, I know I can still shoot better than seven inches. I suspect there is a varying pressure point somewhere on the barrel changing the point of impact. But I don't know how to correct it without putting a tube on it and free floating the barrel. I don't want to modify the gun, so that's out. I've considered trying it with a sling, but haven't done so yet. From everything I read about these early guns, they were supposed to be decent shooters, maybe not sub MOA guns, but certainly better than this. I'm looking for suggestions. Anyone out there had similar problems and what did you do to correct it? Are my expectations just too high? Thanks in advance. |
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My Colt SP1 carbine did better with Lake City M193 than commercial .223. Different weapons of the same series may prefer different loads.Your groups from a sandbag should be 3". My 20" SP1 (on a Nodak stripped lower) will do 2" on a good day and 3" every day.
I am assuming you are using a sandbag rest. When using a rest, I get better groups if I rest my off hand, palm up, on the bag, then the weapon cupped in my open palm. Just my personal experience. |
| My groups sized were almost double the last time I checked: weapon on sandbag vs weapon on hand, on sandbag. Was true with Inland M1 Carbine, Kel-Tec SU-16CA, and 603 on NDS lower. It keeps a certain balance or harmony (I really don't know, but it sounds good!!!) |
| Think I'll second the ammo. Although some guns may group alright with that stuff think I'd try something a little hotter like the M-193 as stated above. Get some Federal and try it. I've never had decent groups in a semi auto with the ammo you listed and Wolf is definately not known for it's accuracy but I've seen some pretty good shooting done with it also inside 100 yds. Search the hometown tab above and make a new friend and see if ya'll can't work it out. I'm gonna assume the barrel isn't fouled. Never had an AR that didn't group better than described. Have had some that would shoot 4" with an occasional flyer but they got sold pretty quick. Most should easy do 2-3" without trying too hard using consistent ammo. 1-12 twist should really like 55gr. Mine do and one jagged hole off a bench isn't uncommon especially with a scope. I'm definately not a pro but have shot a whole bunch for a real long time. |
| I'll try some different ammo. I can see the Wolf not being accurate, but the Remingtons and the handloads shoot fine in my other guns. I would think that out of the four varieties I've tried, one of them should shoot. I'll try the M-193s, maybe some Federal premium, or other high grade ammo. The bore is clean and dry. I've shot plenty of picky guns before and some of them would only shoot really well with one bullet, one load, one type of ammo, but all of them at least tried to shoot with other ammo, maybe the groups were excellent with only one load and passable with others. But not this gun, it's like Mikey; it hates everything. It's very irritating because it's such a nice old rifle. I can't accept that it won't do better than that. Thanks for the tips. Anything else? |
| Get the Federal XM-193 5.56 fmj if range or where you're shooting will allow it. I've had some less than spectacular results with .223 ammo out of a few different AR's over the years. Think govt spec is 2-4 in group on M-193. Should be plenty of this stuff in Az for cheap. Might be the carbine but ammo is a good place to start. Did you buy it used and just start shooting it? Throat erosion and bore guage would tell barrel wear story. Lots of top notch AR folks in Az also. As stated above might be time to make a new friend. |
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Quoted:
ammo is a good place to start........Throat erosion and bore guage would tell barrel wear story. Exactly. Pony up for some "real" premium grade ammo like Black Hills or Federal Gold Medal (assuming they make lighter match loads) and try to find somebody with a bore scope. It's amazing what a bore scope can tell you about ACTUAL bore condition. Also, if you bore is heavily erroded, the rifle may not like boat-tailed bullets. It's kinda hard to really tell what's inside the bore without scoping it. Also make sure things are tight on the rifle. If somehow the barrel nut isn't tight or the front sight tower isn't tight or the front sight post or rear aperature aren't solid, your mileage will vary. It doesn't take much. |
| I picked up some Federal XM-193 today, as well as a couple of other brands, and I'll give it shot this weekend. In response to a couple of posts: I have not scoped the bore, but I've looked it over pretty thoroughly with a light. I can't see any irregularities. I've had the gun for about 10 years but never shot it on paper until recently. I got it from the original owner. I've put maybe 100 rounds through it, and the original owner shot less than that. The barrel is almost as new. Everything is tight, clean and dry. I've checked the flash hider and don't see any issues there. I'll check it out again but I don't think I'll take it off. It's pinned on, which is not a big deal, but once I get it off the gun becomes an SBR. I'm in Arkansas, not Arizona, and yes, we have some AR resources here, but I'm going to try everything I can come up with before I go that route. Thanks to all for the input. I'll update after I shoot it with the new ammo. |
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Quoted:
My SP 1 doesn't shoot to its potential and I need some help. The best I can get it to do is about 6-7 inches at 100 yards. Early 80s gun, all original, near pristine condition, less than 200 rounds down the tube. 16" barrel, including the flash suppressor. Shorty stock. Barrel and chamber are perfect, crown is perfect, headspace is fine, fired brass looks good with no pressure signs or irregularities in the chamber. Sights are original, obviously not target sights, but good enough to shoot a group. Trigger sucks but shooting off the bench it shouldn't make a huge difference. Bullet impacts are scattered, not vertical stringing. Shooting 55 grain soft points, Remington factory ammo. Tried Wolf 55 grain also, as well as a couple of different handloads, 55 grain ballistic tips, and 45 grain soft points. The twist is 1-12, and should stablize bullets of those weights OK. Holes in the paper are clean cuts, no tumbling. I haven't tried anything heavier than 55 grains or lighter than 45. Everything on the gun is tight, clean, and functioning properly. I've shot it off the bench rested on the handguard, rested on the barrel, rested front and rear, prone, offhand, shooting off the magazine, and shooting off the magazine well without a magazine in the gun. Still get 6-7 inches. Tried it at 50 yards and it will do about 4 inches. The same loads shoot through my other guns, so I know it's not the ammo. I can pick up another AR right after this one and shoot two inches at 100 without any trouble, so while my eyes aren't what they once were, I know I can still shoot better than seven inches. I suspect there is a varying pressure point somewhere on the barrel changing the point of impact. But I don't know how to correct it without putting a tube on it and free floating the barrel. I don't want to modify the gun, so that's out. I've considered trying it with a sling, but haven't done so yet. From everything I read about these early guns, they were supposed to be decent shooters, maybe not sub MOA guns, but certainly better than this. I'm looking for suggestions. Anyone out there had similar problems and what did you do to correct it? Are my expectations just too high? Thanks in advance. Quoted:
I picked up some Federal XM-193 today, as well as a couple of other brands, and I'll give it shot this weekend. In response to a couple of posts: I have not scoped the bore, but I've looked it over pretty thoroughly with a light. I can't see any irregularities. I've had the gun for about 10 years but never shot it on paper until recently. I got it from the original owner. I've put maybe 100 rounds through it, and the original owner shot less than that. The barrel is almost as new. Everything is tight, clean and dry. I've checked the flash hider and don't see any issues there. I'll check it out again but I don't think I'll take it off. It's pinned on, which is not a big deal, but once I get it off the gun becomes an SBR. I'm in Arkansas, not Arizona, and yes, we have some AR resources here, but I'm going to try everything I can come up with before I go that route. Thanks to all for the input. I'll update after I shoot it with the new ammo. Um, I don't recall SP1 carbines having pinned flash suppressors from the Colt factory. And you say it's 16" with the flash suppressor? So was it cut at some point? I don't believe your barrel/flash suppressor arrangement is original. Maybe whomever pinned it bungled it all up and that's what's jacking up your groups. Hell, I could be wrong, though, I'm no Colt expert but I don't remember the SP1 carbine I had in the '80s early '90s having a cut/pinned barrel & flash suppressor. |
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Quoted:
. I've put maybe 100 rounds through it, and the original owner shot less than that. The barrel is almost as new. Everything is tight, clean and dry. I've checked the flash hider and don't see any issues there. I'll check it out again but I don't think I'll take it off. It's pinned on, which is not a big deal, but once I get it off the gun becomes an SBR. I'm in Arkansas.  If the barrel on your rifle needs a pinned flashhider to be 16" long it either is NOT A COMMERCIAL COLT SP1 BARREL
or it's a shortened barrel. Likely NOT a 1/12 twist either 
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| I shot the gun today with 55 grain Federal XM-193. I shot off a bench with my hand between the forearm and the bag. There was some improvement. At 50 yards it shot into one inch and I thought the problem wsa solved. I was happy and hopeful. I backed the target off to 100 yards and shot several groups. The best was about five inches. The rest were six to eight inches. The bullets are not tumbling; the holes in the paper are clean cut circles. They just aren't very close together. I'm going to do a trigger job and try it off a machine rest with the same ammo. The 50-yard group seems promising so I optimistic that I'll get it figured out. Answers to a couple of questions: I guess it's possible that the barrel has been cut and the flash hider added later, but if so, it was well done. Fit, finish, and workmanship of upper, lower, and barrel/flash hider, all match and seem to be from the same period. I don't know the nuances of SP1 production but I checked the numbers once and it dated to the early 80s. However, I don't know a way to reference the barrel length as originally manufactured. Does anyone know a way to do this? And the other question: Yes, it is 16 inches, with the pinned on flash hider. I don't have a way to post a picture. I'll check with the original owner for more history. Keep the suggestions coming if you have more. Thank you. |
| In the late 80s, it was not uncommon for folks with SP1 Carbines to cut the barrel and single point the 1/2x28 threads so that with the factory flash hider it measured 16.1" My friend had one. I had one also, but left the barrel factory length. to measure, take a thin rod or dowel and run it down the bore with the bolt closed, with it resting on the bolt face . Mark the rod even with the end of the muzzle. measure the rod and add 1/16" for the rebated area of the bolt face. The barrel extension and locking lugs DO NOT count towards OAL. |
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What are the markings on the barrel? If you could post a pic or two we could tell you exactly what you have more than likely. How good do you shoot with other rifles? Do you know an expert marksman who can shoot a few rds through it? If it only measures 16" from back side of barrel nut to the business end of FH it is definately cut down and more than likely it was a rifle shortened to carbine 16" minimum length and that would explain a pencil barrel with no markings. Doesn't sound like bullet is hitting FH if it groups 1 in. at 50 yds. I'm guessing in Arkansas you are shooting in high humidity around sea level. Was it windy? Were the groups consistent or all over the place?
When I build an AR that doesn't perform as I feel it should I get my ex-marine marksman buddy to give it a try. This usually cost me a little extra ammo but 9 times out of 10 the rifle is dead on and it's me picking up a bad habit whether from breathing wrong, not concentrating or even a little flinch is all it takes. Buddy drills center a few times and the next thing I know I'm hitting center. Works as a confidence builder sometimes. If it won't shoot for him it quickly gets sold and I haven't sold very many. Practice makes perfect. 1 in. at 50 yds should be a little less than 2 in. at 100 so that is basically what the carbine and ammo are supposed to do on a good day. Those who shoot MOA all the time usually practice a lot and use real good ammo. I mostly use scopes and flat tops in my old age for real accurate shooting but my fixed sight stuff is already sighted and I've shot them enough to know where the bullet is going. Do what you want with the trigger but I've had very good luck using M-16, JP and TTI springs to lighten the trigger pull to 5-5.5 lbs. All mine are set this way so regardless of which AR I grab the triggers are all pretty consistent. A little moly lube on the wear points seem to help also. I prefer Colt FCG parts and most who shoot my AR's think I have high dollar triggers. I do spend a little time on them and swap a few parts around to get my desired results. I go by feel and a trigger pull guage and if it doesn't feel right to me I'm gonna swap some stuff around until it does. How much did you shoot it? Try and use the same ammo and shoot it a fair amount (100-200 rds minumum). Different brand ammo will have a different point of impact. If groups get consistent you can make it shoot. If you shot 1 in at 50 yds I'm thinking the carbine is fine. What stock are you using? Collapsible stocks aren't known for good cheek weld. Might be able to put a cheap used rifle stock on it and improve accuracy also. Lots of variables. Rome wasn't built in one day. Good luck! |
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Well, it looks like the shortened barrel suggestion may be correct. I've been comparing this gun to other SP1s and the flash hider is different than any other I've seen. It's longer and vented differently. If it's factory, it's a special order. I do believe that it's period to the manufacture of the gun, or shortly thereafter, if it's not factory. It absolutely matches in fit, finish and wear to the rest of the gun. I have a friend who's a custom smith and who does a lot of AR work. I'm going to have him check it out. I think I'm also going to stick a scope on it for testing. That should greatly reduce any problems caused by my shooting. Thanks for the tips and suggestions. I'll post again when I have an update.
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