Which AGB for Seekins sp10 builders kit / Proof

WoobieJ

WoobieJ

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Apr 28, 2012
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#1
Which adjustable gas block for my build?
Seekins sp10 builders kit
Proof 18” .308 barrel (.875”)
JP VMOS
JP SCS (h2)

A)Rifle speed ( 8733 or 8743?)
B)Superlative
C)JP low pro
 
#3
A couple things to look into or verify:

The Riflespeed typically use straight gas tubes. I don't know which pattern gas system the Proof uses, DPMS or ArmaLite, but if it is ArmaLite length, that gas tube might not be readily available.
The JP 0.875" AGB is longer than most. If the gas journal on the Proof is 1", it will hang over at the front. That will not affect function. It also has the adjustment screw on the side, but access with the Seekins handguard shouldn't be an issue.
 
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#4
Riflespeed .875” adjustable gas blocks are vaporware and unavailable. I think they’re a year overdue by now and the last update was they’re tweaking the spring.
 
#9
mtrmn said:
How about a Seekins?
seekinsprecision.com

Select Adjustable Gas Block

Select Adjustable Gas Block The addition of a suppressor, dirty conditions or even switching ammo are all factors that can lead to undesirable gas settings on your rifle. Our patented design was developed, tested, and fielded by Special Operations who
seekinsprecision.com seekinsprecision.com
Click to expand...
I don’t think that the gas block with lever will fit under the handguard will it?
 
#14
#16
TonyTheTiger said:
I've got several of both. What's wrong with the Seekins?
Click to expand...

I like the idea of the Seekins switch AGB and I'm currently running one on a Custom 6.5CM 18" Bartlein OBR and out of all my AGB's the seekins Carbon Locks the hardest, I tried making some adjustments last weekend and it was locked up so hard the allen head on the end stripped because the screw is a super soft alloy. I'll be switching it out with a SA Adjustable here shortly.
 
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#18
bigjake83 said:
I like the idea of the Seekins switch AGB and I'm currently running one on a Custom 6.5CM 18" Bartlein OBR and out of all my AGB's the seekins Carbon Locks the hardest, I tried making some adjustments last weekend and it was locked up so hard the allen head on the end stripped because the screw is a super soft alloy. I'll be switching it out with a SA Adjustable here shortly.

View attachment 8184763
Click to expand...
Haha good to know. Nice rifle
 
#22
bigjake83 said:
I like the idea of the Seekins switch AGB and I'm currently running one on a Custom 6.5CM 18" Bartlein OBR and out of all my AGB's the seekins Carbon Locks the hardest, I tried making some adjustments last weekend and it was locked up so hard the allen head on the end stripped because the screw is a super soft alloy. I'll be switching it out with a SA Adjustable here shortly.

View attachment 8184763
Click to expand...
Ahhh, yeah I've got no experience with the switch adjustable units..
 
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#24
TonyTheTiger said:
I've got several of both. What's wrong with the Seekins?
Click to expand...

Every gas gun I have an adjustable gas block on has a handguard that completely covers the gas block. The design of the Seekins requires you to access set screws from two directions if you need to make an adjustment. Access one from the side and one from the front. The SLR only needs access from the front and is great to make adjustments. I didn't want to make a hole through the side of my handguards to access the one set screw on the Seekins, so I ditched it into the junk drawer. That's my only gripe about it.
 
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#26
stevieb92 said:
Every gas gun I have an adjustable gas block on has a handguard that completely covers the gas block. The design of the Seekins requires you to access set screws from two directions if you need to make an adjustment. Access one from the side and one from the front. The SLR only needs access from the front and is great to make adjustments. I didn't want to make a hole through the side of my handguards to access the one set screw on the Seekins, so I ditched it into the junk drawer. That's my only gripe about it.
Click to expand...
I suppose that would be inconvenient. All my handguards coincidentally have holes where the screws are.
 
#29
My opinion, if you go with the Superlative, you should take the time to tune it in "bleed-off" mode. It can be a little trickier to tune and doesn't always work with poorly matched gas system lengths/dwell/cartridges. FYI, "bleed-off" will leave soot on the handguard and/or barrel in front of the block. If you think that you will tune only in "restrictive" mode, there are other blocks which are better or equal to the SA.
 
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#30
I went down the adjustable gas block rabbit hole a while ago and I ended up buying 3 different blocks, the Superlative Arms, Riflespeed and the SLR.

If I had to narrow it down to one and I would pick the SLR.

The Riflespeed system is very clever and probably the most tank-like out of the three but I was a bit dissapointed with the machining quality given the super high price and it also didn’t really work with my build. I’m using a 15” rail and I thought I could get away with the longest dial but I just couldn’t get enough of a grip on the dial to adjust it easily. I also thought it was too heavy; this is a minor nitpick but I would have gone for an aluminum dial instead of steel to save weight.

I didn’t use the Superlative because it had this quirk where it would have a false detent click between the actual detent. This made it feel like it had 8 clicks per turn instead of 4. I asked Primary Arms to swap it out for another one and the replacement had the exact same issue. I’m sure I could work around it but I just didn’t like the idea of having false clicks on gas adjustment. I was very interested in the bleed-off mode but a lot of people I talked to who ran the SA block didn’t bother with it because they found it to be finicky. I also didn’t love the loss in velocity from bleed-off mode. Yes, its minor but I’m trying to stretch out my 223 Wylde as far as I can take it so I need all the velocity I can get. The nice thing about it is that you can run it in regular restrictive mode if the bleed off doesn’t work for you.
 
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#31
Leicafan1990 said:
I went down the adjustable gas block rabbit hole a few weeks ago and I ended up purchasing 3 blocks, the Superlative Arms, Riflespeed and the SLR.

I had to narrow it down to one and I eventually selected the SLR.

The Riflespeed system is very clever and probably the most tank-like out of the three but I was a bit dissapointed with the machining quality given the super high price and it also didn’t really work with my build. I’m using a 15” rail and I thought I could get away with the longest dial but I just couldn’t get enough of a grip on the dial to adjust it easily. I also thought it was too heavy; this is a minor nitpick but I would have gone for an aluminum dial instead of steel to save weight.

I didn’t use the Superlative because it had this quirk where it would have a false detent click between the actual detent. This made it feel like it had 8 clicks per turn instead of 4. I asked Primary Arms to swap it out for another one and the replacement had the exact same issue. I’m sure I could work around it but I just didn’t like the idea of having false clicks on gas adjustment. I was very interested in the bleed-off mode but a lot of people I talked to who ran the SA block didn’t bother with it because they found it to be finicky. I also didn’t love the loss in velocity from bleed-off mode. Yes, its minor but I’m trying to stretch out my 223 Wylde as far as I can take it so I need all the velocity I can get. The nice thing about it is that you can run it in regular restrictive mode if the bleed off doesn’t work for you.

I settled on the SLR because I like how easy it is to open it up for regular cleaning . The detent clicks were extremely positive as well. I don’t mind adding Kroil to the adjustment screw after each range trip and periodically cleaning the detent so I know carbon lock won’t really be a concern. It just seems like a very refined and reliable design and it has a long track record which is a plus.
Click to expand...

If you were looking for .750 adjustable gas block you missed out on the best one..

I have been running these in some light weight large frame builds and these little fuckers are awesome!! And you can adjust how much tension you want on the Detent clicker as well and they have a super slim low profile.

After hundreds of rounds and zero maintenance in .308 and 6.5CM they have NOT carbon locked at all.

ar15discounts.com

- Foxtrot Mike Products Click Adjustable Gas Block - .750" - AR15Discounts

The Foxtrot Mike Products Click Adjustable Gas Block offers a precision-machined upgrade for your AR-15. Use the adjustable gas block to finely tune a gas s
ar15discounts.com ar15discounts.com
 
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#32
bigjake83 said:
If you were looking for .750 adjustable gas block you missed out on the best one..

I have been running these in some light weight large frame builds and these little fuckers are awesome!! And you can adjust how much tension you want on the Detent clicker as well and they have a super slim low profile.

After hundreds of rounds and zero maintenance in .308 and 6.5CM they have NOT carbon locked at all.

ar15discounts.com

- Foxtrot Mike Products Click Adjustable Gas Block - .750" - AR15Discounts

The Foxtrot Mike Products Click Adjustable Gas Block offers a precision-machined upgrade for your AR-15. Use the adjustable gas block to finely tune a gas s
ar15discounts.com ar15discounts.com
Click to expand...

Interesting. I didn’t know about these. Good price too. I’m curious how they avoid carbon locking without routine cleaning since it looks like a pretty standard design, similar to the Odin Works blocks but slimmer.

They aren’t on Foxtrot Mike’s website either and only AR15 Discounts seems to have these in stock. I wonder if FM discontinued them.
 
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#33
Leicafan1990 said:
Interesting. I didn’t know about these. Good price too. I’m curious how they avoid carbon locking without routine cleaning since it looks like a pretty standard design, similar to the Odin Works blocks but slimmer.

They aren’t on Foxtrot Mike’s website either and only AR15 Discounts seems to have these in stock. I wonder if FM discontinued them.
Click to expand...

There's actually quite a few retailers that have them on hand I found three today just doing a Google search.
 
#34
bigjake83 said:
There's actually quite a few retailers that have them on hand I found three today just doing a Google search.
Click to expand...

Would you choose the Foxtrot Mike gas block over the Superlative Arms blocks? How easy is it to disassemble the FM for cleaning?

That’s one thing I really like about the SLR. It’s super easy to remove the detent and adjustment screw to flush out the gas block
 
#35
Leicafan1990 said:
Would you choose the Foxtrot Mike gas block over the Superlative Arms blocks? How easy is it to disassemble the FM for cleaning?

That’s one thing I really like about the SLR. It’s super easy to remove the detent and adjustment screw to flush out the gas block
Click to expand...
I run SA blocks 99% suppressed and never remove them to clean. Once on a 308, I had to put some force into the Allen key to get it to change position but then it was fine after I broke the carbon buildup. My advice would be to just adjust it back and forth every so often if you’re worried about it seizing up. That being said, I still don’t even do that. I’m shooting < 1000 rounds a year through most of these guns not thousands.
 
#36
Leicafan1990 said:
Would you choose the Foxtrot Mike gas block over the Superlative Arms blocks? How easy is it to disassemble the FM for cleaning?

That’s one thing I really like about the SLR. It’s super easy to remove the detent and adjustment screw to flush out the gas block
Click to expand...
Yes Id go with the FM over the SLR for a .750 AGB any day, especially since you can buy two FM AGB's and tubes for the price of one SLR.

When I first get any AGBs I usually clean and disassemble them and add some anti-seize to the moving parts, the simplicity of the FM is what makes it so reliable.

To disassemble all you do is remove the detent set screw, spring and detent then just back out the adjustment screw and that's it. I have yet to need to clean or do maintenance on any of my FM AGB's.

I know in your head you think the SLR is super easy to maintain but in real life it's actually a pain in the ass. The leaf style detent spring gets quickly packed with carbon rendering it ineffective to a point you can't even feel the clicks, it is also exposed to the outside elements like dust, dirt and sand. Once the GB becomes fouled you have to disassemble and use a dental pick to scrape out all the carbon, dirt and grime, then lube and Loctite everything back together.

The SLR is also just a restrictive Style AGB, and offers nothing over the FM which has clearly already demonstrated itself to be a more reliable and effective design and a better value, at least with the SA ABG you get a secondary bleed off feature.
 
#37
bigjake83 said:
Yes Id go with the FM over the SLR for a .750 AGB any day, especially since you can buy two FM AGB's and tubes for the price of one SLR.

When I first get any AGBs I usually clean and disassemble them and add some anti-seize to the moving parts, the simplicity of the FM is what makes it so reliable.

To disassemble all you do is remove the detent set screw, spring and detent then just back out the adjustment screw and that's it. I have yet to need to clean or do maintenance on any of my FM AGB's.

I know in your head you think the SLR is super easy to maintain but in real life it's actually a pain in the ass. The leaf style detent spring gets quickly packed with carbon rendering it ineffective to a point you can't even feel the clicks, it is also exposed to the outside elements like dust, dirt and sand. Once the GB becomes fouled you have to disassemble and use a dental pick to scrape out all the carbon, dirt and grime, then lube and Loctite everything back together.

The SLR is also just a restrictive Style AGB, and offers nothing over the FM which has clearly already demonstrated itself to be a more reliable and effective design and a better value, at least with the SA ABG you get a secondary bleed off feature.
Click to expand...

I’m definitely tempted to try out the FM gas block after you explained it’s benefits.

I also reached out the FM about it and I learned that they don’t actually manufacture it. It’s made by a company called Icarus Products and is just distributed by Foxtrot Mike.

I wasn’t able to find out anything about the company itself but the FM rep said they have some kind of patent on the detent mechanism.

What interests me the most is the number of adjustment clicks. 24 is quite a bit more than most detent gas blocks. I’m curious how they get so many clicks on such a short screw.

Also, what antiseize compound do you use when you rebuild your blocks? That sounds like a really good idea.
 
#38
Leicafan1990 said:
I’m definitely tempted to try out the FM gas block after you explained it’s benefits.

I also reached out the FM about it and I learned that they don’t actually manufacture it. It’s made by a company called Icarus Products and is just distributed by Foxtrot Mike.

I wasn’t able to find out anything about the company itself but the FM rep said they have some kind of patent on the detent mechanism.

What interests me the most is the number of adjustment clicks. 24 is quite a bit more than most detent gas blocks. I’m curious how they get so many clicks on such a short screw.

Also, what antiseize compound do you use when you rebuild your blocks? That sounds like a really good idea.
Click to expand...

I use Permatex or Loctite, I prefer the Loctite Copper Graphite.
 
#39
bigjake83 said:
I use Permatex or Loctite, I prefer the Loctite Copper Graphite.
Click to expand...

Thanks.

I also found some threads on other forums where a few people talked about the SLR leaf spring cracking after a few thousand rounds.

So I guess that leaves the Superlative and the Foxtrot Mike. So between those two, which would you pick? Is the SA’s bleed-off option worth the extra $$$? The bleed-off sounds nice if you can get it to run right but if not, you only get 15 restrictive settings while the Foxtrot offers 24.
 
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#42
TheOE800 said:
I’ve watched a Superlative gas block fail on the firing line. Hard pass.
Click to expand...

At this point, I think it might be impossible to build a detent or set screw adjustable gas block that is totally failure proof. The only adjustable blocks I can think of that might be failure proof are blocks with fixed gas port inserts. The only one currently available is the SLR Jet block but it’s basically useless as a fine adjustment tool because it only has a 100% gas insert and a -50% and a -80% gas insert. X2 Dev Group has one coming out later in the year that is basically the same principle but with more port size options but they haven’t announced how many insert options there will be and what sizes they are.



Even though these two designs are unlikely to catastrophically fail, you probably still need to remove the insert periodically and clean it to avoid carbon locking.

I’m honestly tempted to just run a fixed gas block on all my guns and use an adjustable gas key from Sharps or RCA if the build ends of being over gassed or I decide to run a lightweight carrier down the road. The adjustable keys might not be quite as effective as an adjustable gas block but reports of them failing catastrophically are pretty much nonexistent. And if it does fail, you can just throw a milspec backup BCG in your gun and keep running. If your adjustable gas block blows up, you’re potentially screwed.

But I’m probably overthinking this.
 
#44
TonyTheTiger said:
Yes.
Click to expand...

I’m just nervous about putting an adjustable block behind a pin and welded muzzle device when basically every adjustable gas block on the market has failure reports.

You still a fan of those RCA Titanium carriers? I see that they now offer them with adjustable gas keys and I’m tempted to try them out.
 
#45
Leicafan1990 said:
I’m just nervous about putting an adjustable block behind a pin and welded muzzle device when basically every adjustable gas block on the market has failure reports.

You still a fan of those RCA Titanium carriers? I see that they now offer them with adjustable gas keys and I’m tempted to try them out.
Click to expand...
Ah, I overlooked the pinned part. JP has a split block if that helps, can't remember if they make it .875 or not though.
Just looked at the OP again, you're pinning onto an 18" barrel?

And yes, I've got 3 of the RCA TI carriers in circulation now and they are still the kitties titties. I've got at least that many RCA AGK's in use too and my only problem has been when I didn't loctite an adjustment screw and it backed out and turned my gun into a single shot.
 
Last edited:
#46
TonyTheTiger said:
Ah, I overlooked the pinned part. JP has a split block if that helps, can't remember if they make it .875 or not though.
Just looked at the OP again, you're pinning onto an 18" barrel?

And yes, I've got 3 of the RCA TI carriers in circulation now and they are still the kitties titties. I've got at least that many RCA AGK's in use too and my only problem has been when I didn't loctite and adjustment screw and it backed out and turned my gun into a single shot.
Click to expand...

I’m not the OP. I’m sure he has different requirements than me. I’ve just been doing a ton of gas block research for my latest build which will probably have a pinned 14.5 barrel.

With the RCA keys, I’ve heard stories of the set screws walking themselves in, closing off more gas till the gun doesn’t cycle properly. But based on your experience, it seems that they can also back themselves out till the screw falls out, so it sounds like threadlocker is absolutely necessary. I might try this threadlocker I have at work called Threebond 1401C. It’s an external threadlocker you put over the head of the screw after install. It’s has the consistency of superglue but dries clear red so you can see it’s there. The stuff is pretty strong and can withstand temps up to 300’F and it’s easily removed by dissolving it with some drops of acetone. It might be a good application for this.

 
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#49
TonyTheTiger said:
And yes, I've got 3 of the RCA TI carriers in circulation now and they are still the kitties titties. I've got at least that many RCA AGK's in use too and my only problem has been when I didn't loctite an adjustment screw and it backed out and turned my gun into a single shot.
Click to expand...

How’s the staking on those RCA titanium carriers? Are they still using YFS screws? Its not a big deal if they do but I was curious.
 
#50
Leicafan1990 said:
How’s the staking on those RCA titanium carriers? Are they still using YFS screws? Its not a big deal if they do but I was curious.
Click to expand...
You tell me. I don't really get into the whole staking and pinning and mil spec and gauging parts thing, so I don't know if these are good enough for the stake-perfection-gang. I just buy one of everything and shoot it till it breaks, then inspect.
20230721_182210.jpg
 
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