AR Parts Help (Handguard Swap)

LBussy · March 18, 2018, 11:26 AM

I have a PSA Carbine upper and I want to swap the handguards and front sight base out for a full-float handguard. I'm pretty sure I'll need:

Handguard
Barrel Nut
Gas Block

Anything I might be missing?

I don't necessarily want the most tacti-cool part available. Functional is fine so long as the handguard isn't moving around on the barrel nut. M-Loc is preferred, and I don't think I care if the rail is full length or not. Price is important but I'd prefer not to have to replace parts later or run into fitment issues.

Any recommendations based on personal experience for me?

ed308 · March 18, 2018, 11:46 AM

You got it. But, the barrel nut depends on the hand guard. Some come with a proprietary barrel nut that is also used to mount the hand guard. If you read the description for the hand guard, it should tell you what parts you'll need. I've used a lot of Aero hand guards lately. I like them too.

marine6680 · March 18, 2018, 02:04 PM

A pinned gas block may pose a problem for mounting the loprofile gas block later.

The location of the pins may cause a problem for the set screws later. Especially if they are just offset from the ideal location for the lo profile block. Tightening down the set screws may misalign the gas block as the set screws slide into the notches and move the block over.

There are options.

There is a longer low profile block designed to cover up the channels in the barrel from the pins... The screw spacing MAY work better, and not align in an inconvenient manner with the notches in the barrel.

You can get a clamp style gas block rather than the setscrew type... This is an easy solution to the problem...These types I do not trust as much as set screws type, as they can rotate or slip easier... If you go this route, I suggest getting some loctite 680 or 620 retaining compound, or loctite sleeve retaining compound from the auto store (same thing as the other two). You use this in between the gas block and barrel. It's basically metal glue. It is strong and high heat resistant. Any gas block assembled with this stuff is not coming off easy. I have used this stuff before, to hold a bearing onto a round solid steel shaft... I had to destroy the bearing to get it off again, as it wasn't moving easy.

BCM uses the stuff on their loprofile gas blocks... And everyone who has had to remove one of their blocks talks about how difficult is is.

Another solution is to cut down and reshape the existing FSB into a low profile... Use some cold blue to protect the exposed steel.

Other than that... Most free float handguards come with their own special barrel nut, and the tool to install them.

If you go BCM you need to order the tool for their handguards, it's $5 or so... I highly recommend BCM handguards, as they are one of the easiest ones to install. No clocking and aligning of the barrel nut required. I just set my torque wrench to a setting in the middle of the torque spec range and go. They are light and strong to boot. I don't think they offer the original magnesium aluminum alloy type anymore, they are super light, but I prefer the "alpha" type that is standard aluminum alloy. Only a couple oz heavier, and the finish is more robust.

You will also need a new crush washer, as you must remove the muzzle device. Best to use a fresh washer when reinstalling.

Just make sure you have the right tools... You don't need to go all out on the tools, but don't go too cheap. I really like the Magpul BEV block for working on the barrel and muzzle device. I prefer it over the clamshell type for most tastes on the upper. A good solid armorer's wrench will prevent slipping and issues when removing the old barrel nut. Magpul makes a good one, but it is a little pricey... Brownells has one as well under their house brand.

LBussy · March 18, 2018, 03:49 PM

Well it looks like I may need to find different parts than those I was looking at - specifically the gas block. All of the ones I had picked out had set screws. When you consider the probability that the barrel is not finished underneath the base, I might be better off looking for a new barrel. If I go that far I might as well score a new upper. And now my simple change is simpler and more expensive all at the same time.

marine6680 · March 18, 2018, 08:01 PM

It's not hard really... Just need to be prepared.

MagnumWill · March 18, 2018, 10:32 PM

If you have the capability - keep your pinned front sight block and cut it down. I did it with my 20” PSA when i put a free float on it. It takes a day to cut off the sight post, sling mount and bayonet lug, then even it out and paint, but it the fastening method is FAR superior than a clamp or set screw... even though my parts AR has a DEZ set screw front gas block.

But hey, if you’ve got a cutoff wheel you don’t need to buy another gas block...

Nathan · March 19, 2018, 04:51 AM

Quote:

If you have the capability - keep your pinned front sight block and cut it down.

+2 to this. It is a best practice when not replacing the barrel.

Also, I'm pretty sure you are gonna need a gas tube and pin. They tend to seize up n the fsb after a few rounds.

Gas tube punches and some kind of block.

You will likely need a barrel nut tool and a reaction bar.....and a vice.

Mobuck · March 19, 2018, 06:04 AM

If you just want the cosmetics of a railed handguard, get one that used the same mounting system as the standard HG. I tried this and found it uncomfortable.

LBussy · March 20, 2018, 08:22 AM

Quote:

Originally Posted by MagnumWill

If you have the capability - keep your pinned front sight block and cut it down.

I don't think I'm quite "artistic" enough for that. I've seen some pics of some that people have done and I don't believe I could do it justice. I have a 16" barrel and wanted to go with the 13" handguard so my handiwork would be on display for all to see.

Quote:

Originally Posted by Nathan

Also, I'm pretty sure you are gonna need a gas tube and pin. They tend to seize up n the fsb after a few rounds.

Gas tube punches and some kind of block.

You will likely need a barrel nut tool and a reaction bar.....and a vice.

I've never seen the tube seized up, but then again now that I've said that it will happen to me. In the Army we used to lock the doors, tap out that pin and work the tube out so we could clean under it without any issues. Damned armorer was a fascist.

I think I'm good on all the tools though.

Quote:

Originally Posted by Mobuck

If you just want the cosmetics of a railed handguard, get one that used the same mounting system as the standard HG. I tried this and found it uncomfortable.

I'm wanting the mounts actually, but the only drop in replacements with rails that I've seen are the DD ones and they are pretty pricey too. After all that I'd still have the front sight post I'd hoped to get rid of.

The best bet might be to find someone to cut my front sight post for me and smooth it out.

G.barnes · March 20, 2018, 11:19 AM

If you want to keep cost down. Go with a Daniel defense clamp on block and a utg pro freefloat handguard. Just get a handguard at least 10 inches and you'll be good to go.

LBussy · March 20, 2018, 12:57 PM

Quote:

Originally Posted by G.barnes

If you want to keep cost down. Go with a Daniel defense clamp on block and a utg pro freefloat handguard. Just get a handguard at least 10 inches and you'll be good to go.

Sheesh ... that DD gas block is twice the cost of some of the others. Is it twice as good?

That UTG grip is a drop-in right? So no free-floating action.

marine6680 · March 20, 2018, 04:23 PM

$50 is the top end of the price range of lo pro gas blocks... $35 is a good average price for a well made one.

ALG makes a lower cost free float rail as well. I hear good things about them. I have thought about getting one more that once.

Expect to pay at least $150 maybe a little less for a 13" free float handguard that is well made. You may find a sale and spend less. There may be some cheaper options, but I am less familiar with the lower cost options. Usually the cost of low price is high weight, uninspired designs, or poor fit, so I just never went with any, as none appealed to me.

G.barnes · March 21, 2018, 05:32 AM

With a clamp on you want a good material so both pieced heat and cool around the same rate. Otherwise it can cause them to come loose. If you want a drop in rail look at Midwest industries and keep the fsp.

Mobuck · March 21, 2018, 07:21 AM

Railed handguard that easily replaces the standard HG????
ebay is full of them at reasonable prices

LBussy · March 21, 2018, 12:44 PM

I don't mind the money so much if I get what I pay for ... sometimes Daniel Defense seems to charge extra for their name.

To reiterate I want free-floating as well as the mounts, so a drop in replacement (while an easy way to get half what I want) is not in the cards.

marine6680 · March 21, 2018, 07:41 PM

Is the DD worth double some other options?

I doubt that... But clamp on type are not as common as the set screw type, so there are fewer options.

I did find an option though... Yankee Hill makes one.

For the extended type, here is one from Midwest

As for ar a handguard... ALG makes some nice ones. They do have cheaper versions, that skimp on some features. But you must pay an extra $5 to get their wrench, if you go with ALG.

BCM Makes a really nice one, for only $25 more.

LBussy · March 22, 2018, 07:10 AM

Quote:

Originally Posted by marine6680

I did find an option though... Yankee Hill makes one.

Thanks, that looks like a good option and Midway is just down the highway from me. Anything shipped from them is effectively overnight.

Quote:

Originally Posted by marine6680

For the extended type, here is one from Midwest

What's the purpose of the extended one? Does it cover both mounting areas where the FSB was?

Quote:

Originally Posted by marine6680

As for ar a handguard... ALG makes some nice ones. They do have cheaper versions, that skimp on some features. But you must pay an extra $5 to get their wrench, if you go with ALG.

The ALG looks nice. And they make one in PURPLE! I mean come on!

pete2 · March 22, 2018, 10:28 AM

I don't follow the popularity of the full-float handguard unless one is a bullseye competition shooter where sling pressure than throw things off. My 2 rifles shoot very well, neither are floated. Someone enlighten me please.

LBussy · March 22, 2018, 12:13 PM

Because it’s what I prefer really. I mean there’s the extra room to mount whatever, but I just really prefer that look.

It’s funny you say “popularity” because to me the free-float guards are different. I carried an M16 for a long time and the normal grips are what I’m tired of seeing. I guess it’s all perspective.

marine6680 · March 23, 2018, 12:42 AM

Purple?

A man after my own heart.

Problem is, most purples I see are too light for my taste. Seen the Ruger mk IV in a nice shade, I want to get one sometime.

The extended gas block covers up the area from the old FSB better. It also uses three set screws.

As far as the desire for free float... Usually it comes down to a couple factors.

One is the increased room and flexibility with mounting assesories... The other, is the extended gripping area.

LBussy · March 26, 2018, 10:39 AM

Just keeping the info in one place in case I lose it ... I found this gas block which looks like it will cover any shiny spots left when I remove the FSB:

Troy Industries 2" Extended Low Profile Gas Block AR-15, LR-308 Standard Barrel .750" Inside Diameter Steel Matte

It says it's 4140 hardened steel so it should hold up and not erode too horribly.

March 18, 2018, 11:26 AM	#1
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	AR Parts Help (Handguard Swap) I have a PSA Carbine upper and I want to swap the handguards and front sight base out for a full-float handguard. I'm pretty sure I'll need: Handguard Barrel Nut Gas Block Anything I might be missing? I don't necessarily want the most tacti-cool part available. Functional is fine so long as the handguard isn't moving around on the barrel nut. M-Loc is preferred, and I don't think I care if the rail is full length or not. Price is important but I'd prefer not to have to replace parts later or run into fitment issues. Any recommendations based on personal experience for me? __________________ -- Lee Bad decisions make good stories.

March 18, 2018, 02:04 PM	#3
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	A pinned gas block may pose a problem for mounting the loprofile gas block later. The location of the pins may cause a problem for the set screws later. Especially if they are just offset from the ideal location for the lo profile block. Tightening down the set screws may misalign the gas block as the set screws slide into the notches and move the block over. There are options. There is a longer low profile block designed to cover up the channels in the barrel from the pins... The screw spacing MAY work better, and not align in an inconvenient manner with the notches in the barrel. You can get a clamp style gas block rather than the setscrew type... This is an easy solution to the problem...These types I do not trust as much as set screws type, as they can rotate or slip easier... If you go this route, I suggest getting some loctite 680 or 620 retaining compound, or loctite sleeve retaining compound from the auto store (same thing as the other two). You use this in between the gas block and barrel. It's basically metal glue. It is strong and high heat resistant. Any gas block assembled with this stuff is not coming off easy. I have used this stuff before, to hold a bearing onto a round solid steel shaft... I had to destroy the bearing to get it off again, as it wasn't moving easy. BCM uses the stuff on their loprofile gas blocks... And everyone who has had to remove one of their blocks talks about how difficult is is. Another solution is to cut down and reshape the existing FSB into a low profile... Use some cold blue to protect the exposed steel. Other than that... Most free float handguards come with their own special barrel nut, and the tool to install them. If you go BCM you need to order the tool for their handguards, it's $5 or so... I highly recommend BCM handguards, as they are one of the easiest ones to install. No clocking and aligning of the barrel nut required. I just set my torque wrench to a setting in the middle of the torque spec range and go. They are light and strong to boot. I don't think they offer the original magnesium aluminum alloy type anymore, they are super light, but I prefer the "alpha" type that is standard aluminum alloy. Only a couple oz heavier, and the finish is more robust. You will also need a new crush washer, as you must remove the muzzle device. Best to use a fresh washer when reinstalling. Just make sure you have the right tools... You don't need to go all out on the tools, but don't go too cheap. I really like the Magpul BEV block for working on the barrel and muzzle device. I prefer it over the clamshell type for most tastes on the upper. A good solid armorer's wrench will prevent slipping and issues when removing the old barrel nut. Magpul makes a good one, but it is a little pricey... Brownells has one as well under their house brand. Last edited by marine6680; March 18, 2018 at 02:11 PM.

March 18, 2018, 03:49 PM	#4
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	Well it looks like I may need to find different parts than those I was looking at - specifically the gas block. All of the ones I had picked out had set screws. When you consider the probability that the barrel is not finished underneath the base, I might be better off looking for a new barrel. If I go that far I might as well score a new upper. And now my simple change is simpler and more expensive all at the same time. __________________ -- Lee Bad decisions make good stories.

March 18, 2018, 10:32 PM	#6
MagnumWill Senior Member Join Date: March 18, 2009 Location: Central Colorado Posts: 1,001	If you have the capability - keep your pinned front sight block and cut it down. I did it with my 20” PSA when i put a free float on it. It takes a day to cut off the sight post, sling mount and bayonet lug, then even it out and paint, but it the fastening method is FAR superior than a clamp or set screw... even though my parts AR has a DEZ set screw front gas block. But hey, if you’ve got a cutoff wheel you don’t need to buy another gas block... __________________ Those who hammer their swords into plow shares will plow for those who didn't...

March 21, 2018, 12:44 PM	#15
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	I don't mind the money so much if I get what I pay for ... sometimes Daniel Defense seems to charge extra for their name. To reiterate I want free-floating as well as the mounts, so a drop in replacement (while an easy way to get half what I want) is not in the cards. __________________ -- Lee Bad decisions make good stories.

March 18, 2018, 11:46 AM	#2
ed308 Senior Member Join Date: November 5, 2016 Location: DFW, TX Posts: 1,147	You got it. But, the barrel nut depends on the hand guard. Some come with a proprietary barrel nut that is also used to mount the hand guard. If you read the description for the hand guard, it should tell you what parts you'll need. I've used a lot of Aero hand guards lately. I like them too.

March 18, 2018, 08:01 PM	#5
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	It's not hard really... Just need to be prepared.

March 19, 2018, 06:04 AM	#8
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	If you just want the cosmetics of a railed handguard, get one that used the same mounting system as the standard HG. I tried this and found it uncomfortable.

March 20, 2018, 11:19 AM	#10
G.barnes Senior Member Join Date: June 3, 2011 Posts: 182	If you want to keep cost down. Go with a Daniel defense clamp on block and a utg pro freefloat handguard. Just get a handguard at least 10 inches and you'll be good to go.

March 20, 2018, 04:23 PM	#12
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	$50 is the top end of the price range of lo pro gas blocks... $35 is a good average price for a well made one. ALG makes a lower cost free float rail as well. I hear good things about them. I have thought about getting one more that once. Expect to pay at least $150 maybe a little less for a 13" free float handguard that is well made. You may find a sale and spend less. There may be some cheaper options, but I am less familiar with the lower cost options. Usually the cost of low price is high weight, uninspired designs, or poor fit, so I just never went with any, as none appealed to me.

March 21, 2018, 05:32 AM	#13
G.barnes Senior Member Join Date: June 3, 2011 Posts: 182	With a clamp on you want a good material so both pieced heat and cool around the same rate. Otherwise it can cause them to come loose. If you want a drop in rail look at Midwest industries and keep the fsp.

March 21, 2018, 07:21 AM	#14
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	Railed handguard that easily replaces the standard HG???? ebay is full of them at reasonable prices

March 21, 2018, 07:41 PM	#16
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	Is the DD worth double some other options? I doubt that... But clamp on type are not as common as the set screw type, so there are fewer options. I did find an option though... Yankee Hill makes one. For the extended type, here is one from Midwest As for ar a handguard... ALG makes some nice ones. They do have cheaper versions, that skimp on some features. But you must pay an extra $5 to get their wrench, if you go with ALG. BCM Makes a really nice one, for only $25 more. Last edited by marine6680; March 21, 2018 at 07:48 PM.

March 22, 2018, 10:28 AM	#18
pete2 Senior Member Join Date: May 15, 2012 Location: Texas Posts: 2,566	I don't follow the popularity of the full-float handguard unless one is a bullseye competition shooter where sling pressure than throw things off. My 2 rifles shoot very well, neither are floated. Someone enlighten me please.

March 22, 2018, 12:13 PM	#19
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	Because it’s what I prefer really. I mean there’s the extra room to mount whatever, but I just really prefer that look. It’s funny you say “popularity” because to me the free-float guards are different. I carried an M16 for a long time and the normal grips are what I’m tired of seeing. I guess it’s all perspective. __________________ -- Lee Bad decisions make good stories.

March 23, 2018, 12:42 AM	#20
marine6680 Senior Member Join Date: July 24, 2012 Location: Parker, CO Posts: 4,594	Purple? A man after my own heart. Problem is, most purples I see are too light for my taste. Seen the Ruger mk IV in a nice shade, I want to get one sometime. The extended gas block covers up the area from the old FSB better. It also uses three set screws. As far as the desire for free float... Usually it comes down to a couple factors. One is the increased room and flexibility with mounting assesories... The other, is the extended gripping area.

March 26, 2018, 10:39 AM	#21
LBussy Senior Member Join Date: February 26, 2012 Location: Kansas City, MO Posts: 296	Just keeping the info in one place in case I lose it ... I found this gas block which looks like it will cover any shiny spots left when I remove the FSB: Troy Industries 2" Extended Low Profile Gas Block AR-15, LR-308 Standard Barrel .750" Inside Diameter Steel Matte It says it's 4140 hardened steel so it should hold up and not erode too horribly. __________________ -- Lee Bad decisions make good stories.