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Posted: 8/20/2026 4:45:32 PM EDT
| I'm building an AR9 PCC and went to torque the barrel nut only to find out that the upper receiver doesn't fit in the vise block I have. Standard AR15s fit no problem. Is there some difference between the two receivers that make the AR9 not fit? I'm kind of stuck until I find a solution. Any help would be greatly appreciated. Upper/lower is a Spikes Tactical Gen 2. |
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Probably not. I dunno why yours doesn't fit. What type of vise block are you trying to use? Rather, how does it secure an upper receiver? My upper vise block connects to the takedown pin lugs. These are absolutely located the same on AR15 uppers. But, it does also have an extended location to secure longer AR308 uppers. |
| It was actually a friend of mine's that I've used on my AR builds before. Not sure of the brand but it did fit the last AR I built. For whatever reason, the 9 upper I have didn't fit and the block would not completely close around the receiver. I need to get a vise block for myself anyway, so maybe I'll just order a wheeler from Midway. |
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Lemme guess - billet receiver? EDIT - I see you said they were spikes gen 2. Those are absolutely billet or otherwise non-milspec receivers and are not going to work with the clamshell style upper blocks - at least not without some dremel work. Your options are limited. Get one that attaches to the takedown and pivot lugs, modify the clamshell, or - well that's really it unless you want to make something. Reaction rods are out assuming it's a blowback 9. The other extremely risky thing you can do is pin the upper to a standard lower and use a lower vice block to hold both pieces in the vise. If you have a handguard that doesn't require indexing the barrel nut then just gingerly torque to 30 foot pounds. Its not a great idea, but, like I said, your options are limited. |
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If the upper is a flat top, and I’m assuming it is, and you have a vise, then you can put the upper on its side. With the flat of the upper, and the “flat” where the upper fits to the lower, and place those between the jaws of the vise. You can use painters tape, or something, to protect the flat top from mating, though I never had a problem as long as the upper doesn’t move. Tighten the jaws of the vise just enough to prevent the upper from from moving, or twisting. https://imgur.com/a/umUPkfk You will notice that I’m using a couple of pieces of angle iron, and painter’s tape, to protect the upper from the teeth on the jaws. That’s a Bear Creek side charge upper in the picture. |
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Originally Posted By Sailormilan2: If the upper is a flat top, and I'm assuming it is, and you have a vise, then you can put the upper on its side. With the flat of the upper, and the "flat" where the upper fits to the lower, and place those between the jaws of the vise. You can use painters tape, or something, to protect the flat top from mating, though I never had a problem as long as the upper doesn't move. Tighten the jaws of the vise just enough to prevent the upper from from moving, or twisting. https://imgur.com/a/umUPkfk You will notice that I'm using a couple of pieces of angle iron, and painter's tape, to protect the upper from the teeth on the jaws. That's a Bear Creek side charge upper in the picture. This reminded me. Many years ago I bought a upper vise block kit from a company called plastix revolution. It was the type that attached to the pivot and takedown pin lugs. However, it also included a plastic piece that slid over the picatinny rail of the flat top upper. This allowed you to clamp it in the vise sideways, which was much more secure than the other methods. Looks like they're still in business. https://www.plastixrevolution.net/collections/ar15-upper-vise-blocks/products/ar-15-upper-receiver-vise-block-black-pin Credit to SailorMilan2 for reminding me these exist. OP - that is probably your best bet. They're worth having for occasional odd jobs. I am partial to reaction rod style upper blocks for barrel torquing, such as the Magpul BEV block or the Real Avid Lug Lok (I have both). Unfortunately, these aren't compatible with a blowback 9 barrel that doesn't have lugs. |
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This one works well: https://borebuddy.com/product/ar22-ar9-build-block/ |
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Originally Posted By Renaissancemann: This one works well: https://borebuddy.com/product/ar22-ar9-build-block/ Just messing with you. Lol, not often I get to claim the high ground haha. Seriously, though, solid suggestion. Hadn't seen thst one before. Might be getting one of those myself. |
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Thanks for all the info. I'm getting a real avid vice and will find something that will make do or look into all the suggestions here. MUCH appreciated! UPDATE I received the wheeler vise block with bcg insert today. I tried the receiver and it fit perfectly. I was able to finally safely finish my first AR9 build. I will still look into getting one of the other types listed in this thread. |
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These guys get a hard time around here, but I've gotten everything I ordered in a reasonable time. And, their prices are very reasonable. https://abcsportz.com/NcSTAR-VTARUVB-AR15-Rifle-Upper-Receiver-Vise-Block |
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