Gunsmithing Free Float Barrel Clearance
- Thread starter Teleos
- Start date
Re: Free Float Barrel Clearance
the thickness of a business card will do....
the thickness of a business card will do....
Re: Free Float Barrel Clearance
Yes that will do. But extra never hurts. Watch a barrel whip on a high speed camera and it might change you mind about how much clearance you need.
Yes that will do. But extra never hurts. Watch a barrel whip on a high speed camera and it might change you mind about how much clearance you need.
Re: Free Float Barrel Clearance
It really depends on how sturdy your stock is and how heavy your barrel is, if you can sqeaze the barrel Down to touch your stock with ease you might want a little more but typically a business card thickness or two will do fine, that is if you have a decent quality stock.
It really depends on how sturdy your stock is and how heavy your barrel is, if you can sqeaze the barrel Down to touch your stock with ease you might want a little more but typically a business card thickness or two will do fine, that is if you have a decent quality stock.
Re: Free Float Barrel Clearance
I can get a piece of 80 grit sandpaper between my barrel and stock .... took some work but I figured it would be worth it. Im running a factory varmint contour in a HS stock
I can get a piece of 80 grit sandpaper between my barrel and stock .... took some work but I figured it would be worth it. Im running a factory varmint contour in a HS stock
Re: Free Float Barrel Clearance
Just in case anyone finds this thread in a search, I ran 3 pieces of 17 mil (.051 in.) duct tape under the barrel. That was the closest I could get to the .05 in clearance I read somewhere that McMillan uses in it's stocks. I was wary of using just .005 like most people like because I imagined the barrel would whip more than that under recoil.
Just in case anyone finds this thread in a search, I ran 3 pieces of 17 mil (.051 in.) duct tape under the barrel. That was the closest I could get to the .05 in clearance I read somewhere that McMillan uses in it's stocks. I was wary of using just .005 like most people like because I imagined the barrel would whip more than that under recoil.
Re: Free Float Barrel Clearance
Grab the stock in one hand and the barrel in the other.
Flex the two together and note the movement (there will always be some).
This will give you an idea of how much clearance you may need to use a sling or apply some other nonsymetrical pressure to the rifle's stock without directly effecting the point of impact.
I'd want 1/16" at least.
Grab the stock in one hand and the barrel in the other.
Flex the two together and note the movement (there will always be some).
This will give you an idea of how much clearance you may need to use a sling or apply some other nonsymetrical pressure to the rifle's stock without directly effecting the point of impact.
I'd want 1/16" at least.
Re: Free Float Barrel Clearance
i have a Rem700 SPS .308 with 20" varmint contour BBL in a McMillan A5 matched to the contour... it's tight but not touching.
plan to pull them apart and widen the gap a little when i get back from happystan. being so close, it tends to catch shit like small leaves and crud when im hunting. would like to be able to run one of the cillicone impregnated cloths under between the barrel and stock withtout too much trouble, that's a good gap i think.
thats what was great about the AICS... there was what, about 5mm clearance the whole way around! epic.
i have a Rem700 SPS .308 with 20" varmint contour BBL in a McMillan A5 matched to the contour... it's tight but not touching.
plan to pull them apart and widen the gap a little when i get back from happystan. being so close, it tends to catch shit like small leaves and crud when im hunting. would like to be able to run one of the cillicone impregnated cloths under between the barrel and stock withtout too much trouble, that's a good gap i think.
thats what was great about the AICS... there was what, about 5mm clearance the whole way around! epic.
Re: Free Float Barrel Clearance
As per Boltripper, a gap of a business card will do. More gets you some room for air flow that will facilitate barrel cooling.
As per Boltripper, a gap of a business card will do. More gets you some room for air flow that will facilitate barrel cooling.
Re: Free Float Barrel Clearance
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Teleos</div><div class="ubbcode-body"> I read somewhere that McMillan uses in it's stocks. </div></div>
Right.
<span style="font-style: italic"><span style="font-weight: bold">Usually the clearance between barrel and stock is 0.030 for hunting stocks, and 0.050 for tactical stocks.</span></span>
McM site , Faq's.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Teleos</div><div class="ubbcode-body"> I read somewhere that McMillan uses in it's stocks. </div></div>
Right.
<span style="font-style: italic"><span style="font-weight: bold">Usually the clearance between barrel and stock is 0.030 for hunting stocks, and 0.050 for tactical stocks.</span></span>
McM site , Faq's.
Re: Free Float Barrel Clearance
I check the clearance with a dollar bill ~ .006".
I check the bedding, pillars, screw torque, and clearance by holding the rifle at the wrist with one hand and smacking the barrel near the muzzle with the heel of my other hand. The tone should be pure with lots of sustain. It there is buzzing, then there is not enough clearance. If there is not enough sustain, then the bedding connection is not solid enough. In engineering terms, the wave clipping means interference and a low Q means the compliance to recoil is too high.
I check the clearance with a dollar bill ~ .006".
I check the bedding, pillars, screw torque, and clearance by holding the rifle at the wrist with one hand and smacking the barrel near the muzzle with the heel of my other hand. The tone should be pure with lots of sustain. It there is buzzing, then there is not enough clearance. If there is not enough sustain, then the bedding connection is not solid enough. In engineering terms, the wave clipping means interference and a low Q means the compliance to recoil is too high.
Re: Free Float Barrel Clearance
That sounds like an interesting way to test. Thing is, I think the barrel will whip a bit more when you detonate a mini-grenade (cartridge) in the chamber. I think I might try some of that marking fluid in the the forearm if I can find a rifle that's got .005 clearance. Maybe McMillan was just worried about airflow on their tactical stocks.
That sounds like an interesting way to test. Thing is, I think the barrel will whip a bit more when you detonate a mini-grenade (cartridge) in the chamber. I think I might try some of that marking fluid in the the forearm if I can find a rifle that's got .005 clearance. Maybe McMillan was just worried about airflow on their tactical stocks.
Re: Free Float Barrel Clearance
I was taught a simple test that has not failed yet. Place a small blob of modeling clay between the barrel and stock. If you use a sling or bipod to shoot with go to the range and do some firing. If the clay is squished flat you need more room because that is an easy indicator of the barrel hitting the forend.
I have seen the crapola tupperware stocks need over 3/16" to avoid contact when shot from a bipod.
I was taught a simple test that has not failed yet. Place a small blob of modeling clay between the barrel and stock. If you use a sling or bipod to shoot with go to the range and do some firing. If the clay is squished flat you need more room because that is an easy indicator of the barrel hitting the forend.
I have seen the crapola tupperware stocks need over 3/16" to avoid contact when shot from a bipod.
Re: Free Float Barrel Clearance
I have 2" wide electrical tape.
I apply five layers (nominally a total of .025") to the underside of the barrel and then apply release agent over that. The barrel is now properly set up to use as a bedding mold/mandrel for the barrel channel.
Making certain there is significant clearance between the hogged out barrel channel and the barrel with the stock bedded and tightened, apply bedding compound to the channel, then tighten the barrelled action into the stock, allowing any excess compound to escape around the barrel. Squeegee the excess off and allow the compound to cure.
When it's cured, pop out the barrel, remove the tape, and a consistent .025" gap should now exist that conforms perfectly to the barrel contour.
Gaps that are too big can allow foreign matter to become trapped under the barrel, where it's hidden but still capable of providing solid contact. Periodically sweep the gap to ensure there's nothing lurking down in that gap.
Greg
I have 2" wide electrical tape.
I apply five layers (nominally a total of .025") to the underside of the barrel and then apply release agent over that. The barrel is now properly set up to use as a bedding mold/mandrel for the barrel channel.
Making certain there is significant clearance between the hogged out barrel channel and the barrel with the stock bedded and tightened, apply bedding compound to the channel, then tighten the barrelled action into the stock, allowing any excess compound to escape around the barrel. Squeegee the excess off and allow the compound to cure.
When it's cured, pop out the barrel, remove the tape, and a consistent .025" gap should now exist that conforms perfectly to the barrel contour.
Gaps that are too big can allow foreign matter to become trapped under the barrel, where it's hidden but still capable of providing solid contact. Periodically sweep the gap to ensure there's nothing lurking down in that gap.
Greg
Re: Free Float Barrel Clearance
Greg,
Do you mean .005" per layer?
.001" Capton electrical tape is out there, but very expensive.
Greg,
Do you mean .005" per layer?
.001" Capton electrical tape is out there, but very expensive.
Re: Free Float Barrel Clearance
Yes. Sorry; brain fart...
Yes. Sorry; brain fart...
Re: Free Float Barrel Clearance
just to be sure
a remington 700's with the aics is free floating right
just to be sure
a remington 700's with the aics is free floating right
Re: Free Float Barrel Clearance
yes that would be correct Erik
yes that would be correct Erik
