Effect of non-floating hand guard on POI?

B

beavis_m305

Regular
Rating - 0%
0   0   0
Location
New Zealand
Hey CGNer's, I have a RRA Entry Tactical on order, hopefully should be at my door sometime next month. It will be my first AR. I was just wandering what if any effect the standard hand guards will have on accuracy? especially when the barrel starts to heat up and/or shooting off a bipod IE: stringing, groups opening up, POI shift etc. Will probably change them out for a rail system when I feel the need for tacticoolness. And when my bank account recovers!
 
The effect can vary with the barrel length and thickness/metallurgy used. The POI will shift more with the use of a bipod and, the further it's attached from the frame, the more the impact will change. I have noticed a POI in an AR-15 rifle of around 1.5" at 100 m. On the other hand, unless one goes full auto (not likely in Canada), even sustained fire of several 5 rounds per mag, has not resulted in any noticeable POI.
 
Miltiades said:
The effect can vary with the barrel length and thickness/metallurgy used. The POI will shift more with the use of a bipod and, the further it's attached from the frame, the more the impact will change. I have noticed a POI in an AR-15 rifle of around 1.5" at 100 m. On the other hand, unless one goes full auto (not likely in Canada), even sustained fire of several 5 rounds per mag, has not resulted in any noticeable POI.
Click to expand...
ok cool. i had a pressure point bedded Rem 700 that shot great cold but went crazy when you heated the tube up. i guess the AR will be a whole different beast altogether. It's got an R-4 barrel which i understand to be thicker than an M4 profile tube. would be nice to have consistency so i can stretch it's legs a little on bunnies
 
Miltiades said:
The effect can vary with the barrel length and thickness/metallurgy used. The POI will shift more with the use of a bipod and, the further it's attached from the frame, the more the impact will change. I have noticed a POI in an AR-15 rifle of around 1.5" at 100 m. On the other hand, unless one goes full auto (not likely in Canada), even sustained fire of several 5 rounds per mag, has not resulted in any noticeable POI.
Click to expand...

This information is not my own but that of one Kyle Lamb of Viking tactics. In his experience he claims to have produced and witnessed up to 12-18 inches of POI shift at 100 yards by applying pressure to the barrel. A non FF handguard can and does affect the POI of the rifle to varying degrees depending on how you support it and how much pressure is used.

TDC
 
TDC said:
This information is not my own but that of one Kyle Lamb of Viking tactics. In his experience he claims to have produced and witnessed up to 12-18 inches of POI shift at 100 yards by applying pressure to the barrel. A non FF handguard can and does affect the POI of the rifle to varying degrees depending on how you support it and how much pressure is used.

TDC
Click to expand...
Interesting numbers, even if they look excessive. Of course, if one has a rifle (of any kind) with a long skinny barrel and puts force near the muzzle, the barrel will "bend" so POI. The application of force on the barrel also changes the harmonics that will result in POI on their own but not to that extent. So, if one decides to see what is the maximum POI one can get, one can go overboard to situations not likely to have under hunting or range conditions. With my SAN rifle resting it on the bipod or on a rifle rest near the end of the non-free floating handguard, I get around 1.5" POI at 100 m but I don't pull down or push down on the rifle, just the weight of the rifle-scope-ammo combination. With a heavy barrel AR-15 target rifle and a free floating heavy (Al) handguard, I get less than 0.5" POI. I consider these numbers more relevant to actual conditions but I don't go out of my way to test how much deflection I can get either.
 
Miltiades said:
Interesting numbers, even if they look excessive. Of course, if one has a rifle (of any kind) with a long skinny barrel and puts force near the muzzle, the barrel will "bend" so POI. The application of force on the barrel also changes the harmonics that will result in POI on their own but not to that extent. So, if one decides to see what is the maximum POI one can get, one can go overboard to situations not likely to have under hunting or range conditions. With my SAN rifle resting it on the bipod or on a rifle rest near the end of the non-free floating handguard, I get around 1.5" POI at 100 m but I don't pull down or push down on the rifle, just the weight of the rifle-scope-ammo combination. With a heavy barrel AR-15 target rifle and a free floating heavy (Al) handguard, I get less than 0.5" POI. I consider these numbers more relevant to actual conditions but I don't go out of my way to test how much deflection I can get either.
Click to expand...

Very true, I'm simply stating what a well known shooter has published as his experience. The numbers seem excessive, but in any case they are alarming. There is no real downside to a FF forend. There are downsides to non FF forends.

TDC
 
In hind sight i probably just should have ordered it with a FF rail, but I'm not losing sleep over it - can always upgrade later. I kinda like the "standard" look of an AR too though if you know what I mean. Guess I'll just have to shoot it and see what happens. When it gets here. The wait is slowly getting more painful...
 
Don't know what style of shooting you are planning, but for Service Rifle competition, it is just about standard to support the rifle with the hand wrapped around the front of the magazine housing - so no pressure is applied to the barrel no matter which position is used, and no matter how the forend is arranged. The 5/20 is used as a monopod when prone, a bipod not being allowed. A barrel that wanders as it heats up is going to wander no matter what the forend system is.
If you are going to use a bipod, hanging it on the barrel is going to affect things.
 
I've seen 6-12" POI Shift with C7/M16A2/A4 barrels.

However I'm not one to doubt Kyle lamb, and some of his gorilla buddies probably could flex something 18"...
 
It will mainly be used for hunting to start with. I'll be happy if i can hit rabbits out to 200m with reasonable consistancy (slow fire). I'm sure it will be more than accurate enough to bring down deer at bush hunting ranges, and goats out to 300m or so. I should note I'm in New Zealand so as nobody gets mad about hunting with a restricted rifle. I'd imagine I will eventually use it in service rifle comp and/or 3 gun.
 
You must log in or register to reply here.
Back
Top Bottom