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Posted: 9/13/2015 6:48:42 PM EDT
| I have a DPMS RFA2-B24 Flatop rifle and find the supplied hand guard does not allow sufficient cooling when shooting varmints on a hot day. I want to install a well ventilated YHM front hand guard. But there seems to be a difference between the "bore or barrel centerline axis to top of rail distance" stated by YHM and that of my rifle. Obviously, the flat top rail on my rifle needs to match the one on the YHM unit seamlessly. I have tried in vain to get DPMS to tell me what the "bore centerline to top of rail distance" is but failed. To their customer service people it is apparently top secret or something. Does anyone have the correct dimension for this rifle? I know they are suppose to be standardized to some extent but by my calculations the DPMS rail will be about thirty thousandths higher than the YHM unit. Maybe I'm wrong but don't want to buy and then return a product if I don't have to. Thanks in advance. |
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I assume this rifle doesn't have a standard front sight base?
If not, there are 2 heights of detachable front sights that I'm aware of. "Gas block height" and "rail height" I don't buy YHM stuff, but if this is a free float rail, I'd assume it's one of those two. And if you're positive the rail isn't on the same plane as the receiver, then you most likely need a gas block height front sight. (Assuming there isn't another height that I'm not aware of) I would venture to guess DPMS didn't answer your question because it's a weird one, and they probably don't know the answer to it. 
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I'm not entirely sure I'm following the problem....
1) What front sight are you currently using, if any? Do you just have a scope mounted to this? If you are currently not using a front sight and are looking to purchase one, the issue is more than likely not the handguard, it is the gas block, and as milspec stated, you'll need to find a front sight that is labeled "gas block height" and will need to also use a rear sight that is compatible just to be safe ( i think the front sight should compensate for everything it needs to, but I would match the sights to be safe) 2) Does the YHM handguard you want extend past the current Gas block and require its removal??? If you answered, no to question 2, and are currently using a sight mounted onto the RAILED gasblock that rifle comes stock with, what is the problem is the mounted front sight you have now? Just trying to find the actual problem... I dont think it is the receiver. It is a forged A3 flattop receiver and should be spec. The issue is the gas block. |
| Sorry but I must have not made the issue clear. I want to add a YHM front handguard to my DPMS flattop varmint gun. The dimensions given by YHM for the distance from rifle bore centerline to the top of their rail appears to be different than that of my rifle by about .030. But to be sure I need the same dimension for my rifle and cannot get it from DPMS. I run a Leupold scope that is pushed pretty far forward and I need to make sure the rail on the YHM handguard and that on my rifle line up correctly on the same plane. Sorry for the confusion but I appreciate your feedback nonetheless. |
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Your receiver rail height is the standard, you need to buy a free float with a rail that matches that for what you are trying to accomplish. Any free float with an integral top rail will do the trick.
Although as mentioned above, you're better off buying a mount that lets you attach only to your receiver and cantilevers the scope out forward, than running rings off both the receiver and free float Also, don't buy a yhm rail |
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