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Discussion Starter · #1 ·
I recently put an m14.ca scout handguard on my 18.5" LRB build. The Handguard has mounting screws that are making contact with the stock. I don't mean just touching, but significant contact. So much so that out of 5 stocks, only one would go on. This was a SAI synthetic that was flimsy enough to bend in order to get the barreled action on. Its so tight, I might as well have just welded the stock to the handguard.

One would think this would seriously hamper accuracy on the rifle, however that is not the case at all. It shot about 1.5 MOA at 50 yards with both irons and aimpoint. Yes this is the same rifle that shot 5 MOA here:

http://m14forum.com/modern-m14/163701-acceptable-accuracy-ebr.html

I could use a little help about the SHG mount itself. I attached it towards the rear of the barrel, so the rear of it was just shy of contacting the front of the receiver. Within 10 shots, it had shifted to the front, stopping at the front band, a shift of about 1/4-1/2 inch. Is the handguard supposed to be towards the front contacting the front band? Or closer to the rear closer to the receiver? It seems to seat better towards the front band. Shots while it was shifting had some vertical dispersion, but were actually quite decent in accuracy.

I wasn't able to get a hold of m14.ca, but will try again tomorrow.

At the moment, I think I'm just going to leave it as it's shooting well right now.
 

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Discussion Starter · #3 ·
Is it creating more draw pressure at the front end as a result?

Strange...

Tony.
Definitely more pressure. However squeezing the front end doesn't do anything at all.




Marks on the stock from the handguard screws.

At the moment, it's working in the SAI synthetic. Kinda weird putting an SAI plastic on an LRB, but it works and shoots well.
 

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I too have the M14.ca SHG. Not to insult your intelligence, but there is a difference between installing the shg on a standard stock and mounting it on a Black feather system. I would suggest re-reading the instructions just to make sure you weren't reading the wrong ones. If you have already done this, then be patient, Frank will respond to you within a day or two. If you haven't emailed them, then try that as well.

Good luck,

Bob
 

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Discussion Starter · #5 ·
From the instructions:

"Aside from the clearance issues mentioned above, mounting a SHG to a conventionally stocked M14 is the same as with a Blackfeather stocked version, with one major exception: because the Adjustable op Rod Guide is not there to provide instant and secure vertical alignment, extra care must be taken to ensure the top of the rail is true to vertical. "

The clearance issue they refer to says it can be rectified by removing material from the stock. However it is a significant amount of material that I am not willing to do just yet until I decided I want to keep the SHG.

I made sure it was aligned perfectly by using a level on the handguard and a level on top of the receiver.

My point is that the rifle is set up in exactly the wrong way with the stock binding significantly with the rail, and therefore the barrel, but still shooting better than it ever has. Not exactly sure why.
 

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In the gilded halls of Valhala
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Sounds like your action needs to be bedded into a mcm family stock.

Maybe custom inletted.

No wonder it shot poorly in the chassis.

This is just a guess though I have no data. I'd wonder if dome of these ebrs that shoot poorly do so because of OOS reciever geometry?

Seeing how the sage was designed for the m14.




I'd take a Dremel b to that sai stock and don't look back
 

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Lenny,
we designed the M14.CVA SHG primarily for use with the BLACKFEATHER alloy stock, which has extra clearance built in along the top of the forearm. We also tested the SHG with several different stocks. Some would have enough room for the front screws to float clear without any extra clearancing, and some stocks needed a bit of relief. Due to the wide variation in stock configurations at the forend, we can not guarantee that the SHG will fit every stock without clearancing. It takes only a few minutes to make these relief cuts and this is explained in the user documentation.

The fact that your rifle shoots better with direct contact between the hand guard screws and the forearm, indicates to me that there is not enough draw at the forearm. The fact that THIS OCCURS WITH SEVERAL DIFFERENT STOCKS hints at some out of ordinary receiver geometry. Or perhaps the barrel is tilted slightly in the vertoical plane?

The usual EBR stock has no way of compensating or adjusting for these variations in up and down pressure without adding shims at the front or rear of the receiver. However the BLACKFEATHER op rod guide is specifically designed to be adjustable for up and down tension.

PS: Once installed the SHG should not shift at all. If you SHG is shifting, the barrel to HG mounting surfaces are not tight enough. When you tighten up on those hand guard mounting screws, you should get some "draw" on the steel clamps, and they should be rock solid. There should also be a small space between the back of the HG and the front of the receiver. This space is required because most barrels have a CONCAVE angle at the shoulder, and when the barrel is torqued into the receiver this shoulder will often deform out slightly along the outside edge, increasing OD at the barrel to receiver joint.

What brand of barrel did you use?

If the barrel is smaller than GI contours at the critical clamping points, you may need to use some shims under the clamps and/or between the barrel and HG contact surfaces to ensure proper dimensions and correct draw. This is a simple enough procedure, but if you use all three clamps, you need to ensure that the top of the rail remains perfectly straight. This is simple, but it can get a bit fussy.

I lay the rifle, rail side down, on a glass surface [ glass is usually as truly staright as we can get ] then shim and tighten while checking straight and true with a .002" feeler gage under the three mounting surfaces. When the SHG is tightened up at all three locations, and you can't slip that .002" gage under anywhere, this is as good as it gets.

Good luck,
and please keep us posted how this goes for you.
LAZ 1
 

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From the instructions:

"Aside from the clearance issues mentioned above, mounting a SHG to a conventionally stocked M14 is the same as with a Blackfeather stocked version, with one major exception: because the Adjustable op Rod Guide is not there to provide instant and secure vertical alignment, extra care must be taken to ensure the top of the rail is true to vertical. "

The clearance issue they refer to says it can be rectified by removing material from the stock. However it is a significant amount of material that I am not willing to do just yet until I decided I want to keep the SHG.

I made sure it was aligned perfectly by using a level on the handguard and a level on top of the receiver.

My point is that the rifle is set up in exactly the wrong way with the stock binding significantly with the rail, and therefore the barrel, but still shooting better than it ever has. Not exactly sure why.
sounds like you have inadvertantly stiffened the forearm by having the handguard screws coming hard contact with the stock forearm.....the handguard now imparts it's stiffness to the forearm. The handguard to barrel connections may be be changeing the barrel harmonics.....may not be a wrong setup but a new setup based on different parameters.
 

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Discussion Starter · #9 ·
I suppose it's possible the receiver geometry is the cause. My rifle is the third that isn't shooting well in the EBR from recent memory. However mine is an LRB receiver, I don't believe the others were. The criterion barrel seems to be perfectly true in terms of windage. The front site is perfectly centered and the rear is right at the center mark for my zero. I wish all my rifles were like this.

The receiver is LRB, barrel is criterion. I did take measurements of the barrel thickness at the clamping points, however I don't have those measurements with me. I do remember the barrel at the chamber was exactly 1.100" thick.

In the end, the most important thing is that the rifle is shooting well. To hell with how it's "supposed" to be. USNA

I have the Choate folding stock that has been alignment bedded by jon wolfe into this receiver. Last night, I removed a small amount of material from it, and now the barreled action will go in. There is still a lot of contact and binding, similar to the synthetic, although in this case it's in a stock bedded for it. I'll see how it shoots today.
 

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Discussion Starter · #10 ·
Lenny,
we designed the M14.CVA SHG primarily for use with the BLACKFEATHER alloy stock, which has extra clearance built in along the top of the forearm. We also tested the SHG with several different stocks. Some would have enough room for the front screws to float clear without any extra clearancing, and some stocks needed a bit of relief. Due to the wide variation in stock configurations at the forend, we can not guarantee that the SHG will fit every stock without clearancing. It takes only a few minutes to make these relief cuts and this is explained in the user documentation.

The fact that your rifle shoots better with direct contact between the hand guard screws and the forearm, indicates to me that there is not enough draw at the forearm. The fact that THIS OCCURS WITH SEVERAL DIFFERENT STOCKS hints at some out of ordinary receiver geometry. Or perhaps the barrel is tilted slightly in the vertoical plane?

The usual EBR stock has no way of compensating or adjusting for these variations in up and down pressure without adding shims at the front or rear of the receiver. However the BLACKFEATHER op rod guide is specifically designed to be adjustable for up and down tension.

PS: Once installed the SHG should not shift at all. If you SHG is shifting, the barrel to HG mounting surfaces are not tight enough. When you tighten up on those hand guard mounting screws, you should get some "draw" on the steel clamps, and they should be rock solid. There should also be a small space between the back of the HG and the front of the receiver. This space is required because most barrels have a CONCAVE angle at the shoulder, and when the barrel is torqued into the receiver this shoulder will often deform out slightly along the outside edge, increasing OD at the barrel to receiver joint.

What brand of barrel did you use?

If the barrel is smaller than GI contours at the critical clamping points, you may need to use some shims under the clamps and/or between the barrel and HG contact surfaces to ensure proper dimensions and correct draw. This is a simple enough procedure, but if you use all three clamps, you need to ensure that the top of the rail remains perfectly straight. This is simple, but it can get a bit fussy.

I lay the rifle, rail side down, on a glass surface [ glass is usually as truly staright as we can get ] then shim and tighten while checking straight and true with a .002" feeler gage under the three mounting surfaces. When the SHG is tightened up at all three locations, and you can't slip that .002" gage under anywhere, this is as good as it gets.

Good luck,
and please keep us posted how this goes for you.
LAZ 1
I reinstalled the SHG yesterday, this time moving it back and forth to find where it naturally wanted to sit. I used levels to make sure it was perfectly aligned with the receiver. What amount of torque should I put on the screws?
 
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