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Discussion Starter #1
I posted this on other forums looking for some answers. Please help

I own a Smith and Wesson M&P15T. I am experiencing a no feed situation regular ly. I have 5 30 rounds mags (Same make as what came with the gun) and one 20 round mag. Today, I shot used the 20 round mag first, and after the first shot, it did not feed, I fed the next one and after that I did not have any issues. I then loaded a 30 round mag, and first 5 rounds would not feed automatically, and after that I had not problems with the mag. The next 4 mags I had nothing but problems with, sometimes it would not feed at all and the next it catch the ammunition half way up and jam the gun. The gun was cleaned and lubed. This is my 3rd outing and same results. Any suggestions? I am thinking about sending it back to Smith and Wesson, but hate to part with it for weeks if I can fix it myself.



Oh, I am shooting American Eagle .223 Rem. 55 Grain FMJ Boat Tail and Federal XM193 5.56MM M193 Ball ammo 55 Grain. Did not notice a difference between how they fed.
 

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Sorry to hear of your rifle's problems. I have heard of loose gas blocks on these rifles that would explain your issues. Call S&W and I'm sure they will do a fix that will last. Let usknow what they say.
 

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I agree. It's probably the gas block. Some of these (especially earlier ones) seem to be prone to being loose. I guess they didn't loctite them.
 

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I can't seem to move the gas block. The HEX bolts have been locked in with indenting the sides and pushing the steel into the HEX bolts, and from I understand the earlier Gas blocks were aluminum and I checked mine with a magnet and it is steel.
 

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rimler said:
I can't seem to move the gas block. The HEX bolts have been locked in with indenting the sides and pushing the steel into the HEX bolts, and from I understand the earlier Gas blocks were aluminum and I checked mine with a magnet and it is steel.


Are you sure you're not looking at your gas key (attached to the bolt carrier) and not the gas block? The gas block is under the rail on your M&P15T, you'll have to remove the bottom portion of the rail to access it.
 

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gotm4 said:
[quote name='rimler']I can't seem to move the gas block. The HEX bolts have been locked in with indenting the sides and pushing the steel into the HEX bolts, and from I understand the earlier Gas blocks were aluminum and I checked mine with a magnet and it is steel.


Are you sure you're not looking at your gas key (attached to the bolt carrier) and not the gas block? The gas block is under the rail on your M&P15T, you'll have to remove the bottom portion of the rail to access it.[/quote]



Good catch...
 

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Discussion Starter #8
I just checked it. It is aluminum, and there appears to be burnt powder residue where the gas tube goes into the block and where the tube connects to tube on top of the receiver. Can I assume this is a problem.
 

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A little leakage is normal. But the problem lies in that the block is a different metal than the barrel and it's only set screwed to the barrel and not dimpled for the screws nor pinned to prevent movement.



S&W at sometime soon will be using pinned steel gas blocks on new M&P15Ts. I don't know when this change will occur. S&W will likely just dimple your current barrel for the gas block. If it were mine I would replace the gas block with either a VLTOR steel on or a LaRue steel gas block and dimple the set screws or have it pinned.
 

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Discussion Starter #10
gotm4 said:
A little leakage is normal. But the problem lies in that the block is a different metal than the barrel and it's only set screwed to the barrel and not dimpled for the screws nor pinned to prevent movement.



S&W at sometime soon will be using pinned steel gas blocks on new M&P15Ts. I don't know when this change will occur. S&W will likely just dimple your current barrel for the gas block. If it were mine I would replace the gas block with either a VLTOR steel on or a LaRue steel gas block and dimple the set screws or have it pinned.


I like your idea, what exactly do you mean wehn you say dimple the set screws or have it pinned.
 

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Discussion Starter #11
rimler said:
[quote name='gotm4']A little leakage is normal. But the problem lies in that the block is a different metal than the barrel and it's only set screwed to the barrel and not dimpled for the screws nor pinned to prevent movement.



S&W at sometime soon will be using pinned steel gas blocks on new M&P15Ts. I don't know when this change will occur. S&W will likely just dimple your current barrel for the gas block. If it were mine I would replace the gas block with either a VLTOR steel on or a LaRue steel gas block and dimple the set screws or have it pinned.


I like your idea, what exactly do you mean wehn you say dimple the set screws or have it pinned.[/quote]



My next question is: What is the best way to get the gas block off, it was stated that the aluminum gas blocks were actually pressed on.
 

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rimler said:
I like your idea, what exactly do you mean wehn you say dimple the set screws or have it pinned.



My next question is: What is the best way to get the gas block off, it was stated that the aluminum gas blocks were actually pressed on.


You have to make sure the gas port in the barrel is in alignment with the gas port in the gas block. Then tighten one of the set screws (I tighten the front one) then remove the rear one and drill about 1/16" is or so into the barrel. Then add red Loc-Tite the the rear screw and tighten in down firmly into the gas block. Then remove the front set screw, degrease and apply red Loc-Tite and reinstall. I only dimple one of the screws into the barrel.
 

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Discussion Starter #13
gotm4 said:
[quote name='rimler']



I like your idea, what exactly do you mean wehn you say dimple the set screws or have it pinned.



My next question is: What is the best way to get the gas block off, it was stated that the aluminum gas blocks were actually pressed on.


You have to make sure the gas port in the barrel is in alignment with the gas port in the gas block. Then tighten one of the set screws (I tighten the front one) then remove the rear one and drill about 1/16" is or so into the barrel. Then add red Loc-Tite the the rear screw and tighten in down firmly into the gas block. Then remove the front set screw, degrease and apply red Loc-Tite and reinstall. I only dimple one of the screws into the barrel.[/quote]



What is the best way to remove the existing gas block, if in fact S&W did press fit the gas block onto the barrel? And by the way thanks for your help.
 

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rimler said:
What is the best way to remove the existing gas block, if in fact S&W did press fit the gas block onto the barrel? And by the way thanks for your help.


It isn't press fit, just loosen the screws and it just slides on and off the barrel. Nothing on the AR family of rifles is 'press fit'.
 

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I have the 15T and have put about 600 rounds through it with no problems whatsoever but would it be a good idea to send off the upper to someone that would replace the block and correctly install it? Is this a problem that can likely show up later? I would prefer to have it done proactively rather than send it in when it fails. I prefer to send it to a private company rather than S&W. S&W would probably void my warranty due to new trigger, stocks. grip etc. Is there a suggestion on who can/will do that work for me? Thanks for any help here.
 

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chuckles said:
I have the 15T and have put about 600 rounds through it with no problems whatsoever but would it be a good idea to send off the upper to someone that would replace the block and correctly install it? Is this a problem that can likely show up later? I would prefer to have it done proactively rather than send it in when it fails. I prefer to send it to a private company rather than S&W. S&W would probably void my warranty due to new trigger, stocks. grip etc. Is there a suggestion on who can/will do that work for me? Thanks for any help here.


If you plan to run it hard or possibly use it for self defense I would recommend changing out the aluminum gas block for a steel or stainless steel VLTOR gas block and have at least one of the screws dimpled into the barrel and use red Loc-Tite on both.
 
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