M14 Forum banner
1 - 20 of 34 Posts

·
Registered
Joined
·
17 Posts
Discussion Starter · #1 ·
I just put an SAI Scout Squad on the Archangel Stock with a Bassett low Piccatinny mount and a Zeiss Conquest 6-20x50. Five shot groups were from the bench using a Harris bipod and 168gr FGMM. The attached pics show my dilemma with 3 shots high and 2 shots low. This happened 2 groups in a row.

I routinely shoot 1 hole 5 shot groups from bolt guns and a bipod so I do not believe it was me causing the split.

Your suggestions as to what would cause that will be appreciated.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #4 ·
That is frustrating, the forum rotated those pics in the upload somehow. The pics above are now sideways. The 3 shots were about 2 inches above the 2 shots. But for whatever is happening ??? With the gun, they would be sub MOA 5 shot groups with Federal Gold Metal Match 168gr factory ammo.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #8 ·
I put the stock, Bassett mount and scope on all this week. I never shot the rifle with iron sights with the Archangel stock. With the plastic SAI stock and iron sights, I never noticed groups that were split high and low. I only shot cheap ammo though. My groups with factory iron sights tend to be large so it seems wasteful to shoot FGMM with iron sights. I guess I could develop that skill, but that's not what I am inclined to do yet.

I thought that i might try groups with the old stock to see if maybe the mount was moving back and forth. The only problem is that was my last box of match ammo so i am not sure I will be able to tell with cheap ammo. I suppose I could try one of my reloads that work we'll in some of my bolt guns and see if I get the same pattern.

One of my friends says he'll bet it's the mount ???
 

·
Registered
Joined
·
7,253 Posts
I put the stock, Bassett mount and scope on all this week. I never shot the rifle with iron sights with the Archangel stock. With the plastic SAI stock and iron sights, I never noticed groups that were split high and low. I only shot cheap ammo though. My groups with factory iron sights tend to be large so it seems wasteful to shoot FGMM with iron sights. I guess I could develop that skill, but that's not what I am inclined to do yet.

I thought that i might try groups with the old stock to see if maybe the mount was moving back and forth. The only problem is that was my last box of match ammo so i am not sure I will be able to tell with cheap ammo. I suppose I could try one of my reloads that work we'll in some of my bolt guns and see if I get the same pattern.

One of my friends says he'll bet it's the mount ???
I know you sound like you are sticking with the scope. (That zeiss is a excellent scope) But don't understatement those iron sights. If you have trouble seeing targets at 100 yards check into getting glasses.
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #12 ·
Was it with one magazine? Maybe its the alternating rounds feeding into the chamber a little differently. Try another magazine to see if it goes away.
I was alternating magazines so I don't think so. I only shot 5 5-shot groups with the match ammo and all groups had that same sort of issue: some high, some low. The 2 I posted were just more pronounced.

The more I think about it, that Bassett mount moving back and forth seems like it would be the issue???
 

·
Registered
Joined
·
17 Posts
Discussion Starter · #13 ·
I know you sound like you are sticking with the scope. (That zeiss is a excellent scope) But don't understatement those iron sights. If you have trouble seeing targets at 100 yards check into getting glasses.
I have nice new glasses (2 pair). I enjoy iron sights. With this rifle, the front post covers one of those orange dots which is hard to see at 100 yards even with new glasses. I do understand the capabilities and that there is a skillset for the iron sights. I like firing off multiple shots with iron sights and hitting metal dingers at 150-300 yards, but I also like putting on a scope, reloading and shooting very tight groups. For this rifle, with a scope, I am hoping to get it to shoot my hand loads (or FGMM) at 1 MOA with a bipod. When those first 3 shots of FGMM hit close, I thought maybe I was there, but then 2 low shots. The next group was 2 high, 1 low, 1 high, 1 low.
 

·
Super Moderator
Joined
·
11,174 Posts
Was it with one magazine? Maybe its the alternating rounds feeding into the chamber a little differently. Try another magazine to see if it goes away.
I was alternating magazines so I don't think so. I only shot 5 5-shot groups with the match ammo and all groups had that same sort of issue: some high, some low. The 2 I posted were just more pronounced.

The more I think about it, that Bassett mount moving back and forth seems like it would be the issue???
3/17 is more correct than people think, many of us match shooters test magazines for this reason. Spring pressures between the two are different, so we are looking for 3 or 4 mags that have the same or close too the same spring pressure, when loaded they support the bolt in the same or close too the same position.

Once you have 3 or 4 mags or a pair that group close too each other number them and keep them together 1-2/3-4. 1 and 2 stay together 3 and 4 together try not too mix 1 with 4 as you may get a grouping like you posted. 2 and 3 paired together would see some shift but not as much as 1 and 3 or 1 with 4 would show.

After you have a pair that group together, you can polish where the case drags on the follower and the underside of the feed lips, for the same reasons. So the rounds strip off the top using the same amount of effort.

Don't knock it, I been using the same 3 mags for years in every rifle I've used or owned. All 3 group on top of each other, my best or #1 of the three is my Offhand mag. Sitting Rapid/Prone Rapid magazines #1 and #2 are used. Slow Prone is back too #1. Magazine #3 is loaded with 8rds and is held in reserve in case I screw stuff up during the rapid fire stages and is kept within easy reach.
 

·
Registered
Joined
·
1,679 Posts
Since you just put everything together, I would suspect that the action is just settling into the stock. It used to be said, if an action was taken out of a stock, that it would take about 20 shots for the action to settle back in place once it was returned to the stock.
I know you have it in an Archangel stock, and those have very tight lock ups, but it may be a case of the stock settling into place, or the stock adjusting to the action.
I would shoot it a few more times to see what happens. If you continure to get two sets of groups like that, then I would suspect you might have POI changes due to heating or rubbing.
 

·
Registered
Joined
·
15 Posts
Wouldn't a mag with eight rounds in it put more pressure on the bolt than a mag with two rounds in it, assuming that they had the same spring pressure when empty ? As the mag emptied the pressure would lessen with each round. Am I missing something here ? Will three hundred yard groups string when using the eight round loaded mag after the mag with two is fired ?
 

·
Super Moderator
Joined
·
11,174 Posts
Wouldn't a mag with eight rounds in it put more pressure on the bolt than a mag with two rounds in it, assuming that they had the same spring pressure when empty, as the mag emptied the pressure would lessen with each round. Am I missing something here
Yes it would apply more pressure when loaded, but not all magazine springs are the same stiffness. Your looking for the few that agree with each other and with the rifle.


Will three hundred yard groups string when using the eight round loaded mag after the mag with two is fired ?
They shouldn't if you did your testing with 8rds in the magazine @ 200yds, if it strings at 300 that's a shooter/operator era sighting/head position/elbow/breathing and or sling adjustment.
 

·
Registered
Joined
·
15 Posts
You have to shoot your first two shots in a rapid fire string from a mag with two rounds in it, and then go to a mag with eight, as you are well aware, being a hi-power shooter. Even if your two mags matched spring rate, they would not be equal loaded. One would have two rounds compressing the spring, and one would have eight compressing it. More compression on the bolt with the second one.
You have brought up a point that I never considered before. Shooting at the six hundred the same mag, loaded with one round each time, so no problem there. But the three hundred is a mag change, hence more pressure on the bottom of the bolt. I think I will test my match gun at three hundred over a bench to see just how much difference it will make. I just never thought of this before, and since I just put a new barrel on my rifle, it should show me the differences. It is a rear lug gun, and very accurate.
 

·
Super Moderator
Joined
·
11,174 Posts
You have to shoot your first two shots in a rapid fire string from a mag with two rounds in it, and then go to a mag with eight, as you are well aware, being a hi-power shooter. Even if your two mags matched spring rate, they would not be equal loaded. One would have two rounds compressing the spring, and one would have eight compressing it. More compression on the bolt with the second one.
You have brought up a point that I never considered before. Shooting at the six hundred the same mag, loaded with one round each time, so no problem there. But the three hundred is a mag change, hence more pressure on the bottom of the bolt. I think I will test my match gun at three hundred over a bench to see just how much difference it will make. I just never thought of this before, and since I just put a new barrel on my rifle, it should show me the differences. It is a rear lug gun, and very accurate.
I'm telling you there is a big difference, don't believe me ask Art Lupino or Nez..........
 
1 - 20 of 34 Posts
Top