Expo Arms Low Profile Gas Block - .750"

Manufactured by Expo Arms
Manufactured by Expo Arms
21 Reviews

In Stock

Standard orders will ship out in 1 business day (M-F) if ordered by 3:30 pm CST. FFL orders will ship within 5 business days or less as long as we have the information for the transfer destination. NFA items will take longer to ship and are dependent upon ATF processing times.

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The Expo Arms Low Profile AR Gas Block is a precision machined steel gas block designed for use with barrels that feature a .750" gas seat diameter. Machined from high quality 4140 chrome moly steel with a durable manganese phosphate finish and features a secure dual-set screw mounting design that will fit under almost any free floated handguard system on the market! The set screws included with this AR gas block are made by McMaster-Carr and on top of being black-oxide alloy steel, they feature serrations on the cup edge to grab onto any surface creating a mechanical lock that will prevent loosening even without Loctite. Proudly made in the U.S.A.

  • 4140 Steel construction
  • Manganese Phosphate finish
  • .750" Internal Diameter
  • Low profile design
  • Black-oxide alloy steel set screws
  • Knurl-grip cup-point design prevents loosening
  • Made in the U.S.A.
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BrandExpo Arms
Gas Seat Diameter.750
TypeSet Screw
Weight1.2 Oz
California Prop 65 warning

 WARNING: This product can expose you to chemicals, which are known to the State of California to cause Cancer and Reproductive Harm. For more information go to www.P65Warnings.ca.gov.

Ratings & Reviews

21 reviews


Great Customer service with a problem gas block.

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I purchased this gas block and it was a little snug going on to my barrel. I tapped it a little with a piece of 3/4" PVC and plastic mallet but it would not advance onto the barrel any more that it had and it was now stuck. I cut it off and left a 1 star review. PA Customer Service contacted me and we talked about the problem. My barrel is .75". To make a bad experience great, PA offered to reimburse me even though I had not intended to ask. Great customer service. Bottom line, if the gas block does not slide on fairly easy with the set screws removed, stop and check things out before resorting to force.

Quality plus price

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Perfect fit! Very easy install. Very good quality for the price. Combine that with the lightning fast shipping!

Quality with a reasonable price!

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Item is perfect for my change over to a low profile on my PSA A2 front sight/gas block. And the price is great. Ordered and in 2 days the parts were at my front door!

Good Budget Block

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Installed without issue. My gas tube does rattle in it, not sure if that is the tube being under sized or the block being over sized. Either way, no cycling issues.

Perhaps a dud

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Fit was too tight but after polishing it with fine grit sandpaper and steel wool, it fit. That’s a simple fix however, the main issue was the screws. They would strike sparks as you tighten them, they shed some metal shavings from the threads, and eventually broke an Allen key while trying to get the screws to engage with the barrel and it still would not hold onto my ballistics advantage govt profile barrel. No matter how hard I try to get them to tighten they would not stay in place.
I ended up going to a local shop to pick up a different gas block.

Excellent customer service after part issue


I had an issue with the set screws not tightening all the way. The fit on the barrel was fine, but the set screws would not go past a certain point. I used the chat function on the website and they sent me a new one that day. I was also contacted by customer service to verify i was happy with the service i received. This is probably the best customer service i have had. Very happy!

Expo Arms Value priced, Excellent Quality

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Comes nicely packaged. Excellent fit and finish, no machine marks and fit on barrel perfectly. Way better than the price would suggest.



wish all companies would use PARMS C/service’s policies and altitude in solving problems. I will purchase items FIRST from PARMS
(if offered)

Nice Gas Block

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Just got done installing on a stainless M4 profile barrel. The gas block slid on perfect and looks good. The set screw spacing is .45 for those that dimple their barrels. I also like the way Expo packages their items. Happy with price and quality of product.

You get what you pay for

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Get what you pay for. I tried three different gas tubes and none would slide into the gas tube channel on this gas block more than 1/4". I ended up filing and sanding the inside of the gas tube channel in order to get the tube to fit. Seems fine otherwise but i don't expect to have to modify a new part when i get it.