Rastoff
US Veteran
OK, so that leads to this question, how is the forearm causing your front sight to move around? I'm not trying to be a smart alec here, I really do want to learn so I might be able to help someone else in the future.
mp 15, brand new with loose rail
- Thread starter oregonsquatch
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cyphertext
US Veteran
I'm trying to replicate this myself, and I am just not following.
I have my son's M&P 15-22 with a vertical grip on it. His grip has some play in it because he took it off his airsoft gun. I can wiggle the grip right and left, but when I mount the rifle and use the grip to pull it back into my shoulder, the rifle is solid. It doesn't move.
Are you shooting right handed Tromper? It sounds like you are pulling to the left with the grip vs. straight back. Am I understanding this correctly?
Argonnakid
Member
Hey, I like my 2nd gen 15T. Or 3th gen. Or whatever generation I have. I don't think the UTG gets a fair shake sometimes.
Argonnakid
Member
That's OK, I know some people just won't get it. It sounds odd but it's just the way it works. You have to try it. Naturally if you hold the rifle still it will feel solid. The problem lies in how the eye views the sights when they are in different positions and how the shooter will then move the barrel to align the sights. When there is movement of the weapon whilst the rail is held still the shooter will move the barrel to compensate for the perception of the sights being in a different place. I guess you just have to try it to see it. If someone tried to explain this to me verbally I'm not sure I would grasp it either.
Kadonny
Member
I don't think you can compare that one to the typical 2 piece drop in rail... for $351 MSRP, it better lock up tight!
Then I feel really good that I only pad $110 for mine off of Gunbroker
(vertical forearm included).The point being is that a blanket statement was made by MichiganScott that all drop in rails will have movement, and that's just not true.
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cyphertext
US Veteran
Then I feel really good that I only pad $110 for mine off of Gunbroker
The point being is that a blanket statement was made by MichiganScott that all drop in rails will have movement, and that's just not true.
Point taken... should be majority, as there will always be exceptions.
ChattanoogaPhil
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Ive got an old UTG 2-pc on an old Bushmaster upper in the AR parts bin closet... man I need a bigger closet. Anyway... keep those four screws tight and it will not move, period. As a bonus for scrounging around this morning... I found a LaRue Index Clip on the rail. Always can use another one of those. 
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Ive got an old UTG 2-pc on an old Bushmaster upper in the AR parts bin closet... man I need a bigger closet. Anyway... keep those four screws tight and it will not move, period. As a bonus for scrounging around this morning... I found a LaRue Index Clip on the rail. Always can use another one of those.
Nice....that rail probably weighs 5 lbs......
Argonnakid
Member
Are those airsoft rifles? UTG for the win
Ok, I respect the your opinion in that you don't like how I set up "MY" rifles. But you seem to have a negative comment for all the other forum member's as well.
it was tongue and cheek.......do you really take these forums that seriously? Usually when emoticons are used, that is a tell tale sign of hyperbole and sarcasm.
muzzleblasted
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I've noticed on my M&P the spring pressure on the delta ring seems much lighter than on my other guns. I've found that I can switch a handguard between different guns of mine and it always has more slop on the Smith. I think they could benefit from a stronger spring.
Argonnakid
Member
Sorry, just cranky as all get out. Too many days working, not enough days shooting.
Go shoot....the weather is great this weekend in Hampton Roads! You check out C-2? Or you can drive a ways up north to Chickahaminy for free. Fort Eustis has a 200 yard range for $30 a year, but you have to be military......trying to go this weekend
Chuckiebob
Member
BluGrass
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This may be a newb question but should you not mount a front sight to a drop in rail?
I'd rather die on my feet than live on my knees
Rastoff
US Veteran
That's correct. Do not mount the front sight to a drop in rail/forearm. But, why Rastoff? I'm so glad you asked that young Padawan...
No matter how tight you get the drop in forearm, there will always be a tiny bit of movement. If the front sight is on the forearm, it will move with the forearm and your Point of Impact (POI) will constantly be changing. Any movement of the front sight will affect the POI. So, if the front sight is attached to the barrel, it will be rigid and won't move with the forearm.
This is why an optic should be mounted to the receiver. The receiver is fixed to the barrel. Thus, the two move as one.
This is also why a free float forearm is such a good idea. Because the free float forearm is attached only to the receiver, any flex in the forearm won't affect the sights. Thus, when you put your forearm on a bag, rest or bipod, the rest won't cause the barrel to move like it would with a drop in forearm. However, if the front sight is affixed to a free float forearm, that forearm had better be rigid or any movement will change the POI.
Any pressure on the barrel can affect POI. I know the barrel seems very stiff, and they are, but they still bend if you put it in a rest. They only bend a tiny bit, but that is enough to change you POI a couple of inches at 100 yards. So, if you have a drop in forearm and want to use a rest, place that rest as close to the receiver as you can. This will reduce the lateral pressure on the barrel. This is why most bolt action guns have stocks that don't touch the barrel. The effect is the same as a free float barrel.
Typically drop in rails will introduce some movement, so they aren't ideal for mounting sights. Grenade launchers on the other hand may not matter so much..
