Fourteen guns, by the numbers
| Gun | BPM | Stroke | Rated aluminum rivet | Shank | Weight | Where |
|---|---|---|---|---|---|---|
| ACAT 2X | 2,580 | 2 1/4" | 5/32" | .401 | 3.12 lb | US · Yardstore |
| ACAT 3X | 2,160 | 2 7/8" | 3/16" | .401 | 3.25 lb | US · Yardstore |
| ACAT 4X | 1,740 | 3 1/16" | 1/4" | .401 | 3.5 lb | US · Yardstore |
| ACAT Corner | 2,700 | 2 1/4" | 3/16" | .401 short | 2.63 lb | US · Yardstore |
| ACAT 5X | 1,500 | not listed | 1/4" | .498 | 5 lb | US · Yardstore |
| ACAT 9X | 1,140 | not listed | 5/16" | .498 | 5.5 lb | US · Yardstore |
| ACAT 7X | 900 | not listed | 3/8" | .498 | 5.5 lb | US · Yardstore |
| ATS Pro 2X | 2,580 | 2 1/4" | 1/8" | .401 | 2.7 lb | UK/EU · LAS |
| ATS Pro 3X | 2,160 | 2 7/8" | 3/16" | .401 | 3.4 lb | UK/EU · LAS |
| ATS Pro 4X | 1,740 | 3 1/16" | 1/4" | .401 | 3.6 lb | UK/EU · LAS |
| Sioux 270A-2 | 2,500 | 2" | 5/32" | .401 | 3.0 lb | UK/EU · LAS |
| Sioux 270A | 2,000 | 3" | 3/16" | .401 | 3.2 lb | UK/EU · LAS |
| Sioux 270A-4 | 1,700 | 4" | 1/4" | .401 | 3.5 lb | UK/EU · LAS |
| ATS 2602A | 0–2,600 | not listed | "3X power" (seller) | .401 | 3.2 lb | UK/EU · LAS |
Every figure is the seller's listing, checked 29–30 September 2026; each name links to the page with its source. Rated capacity is the maker's claim, not a test result.
How to choose, per the FAA Handbook
Size is the largest rivet the gun drives continuously. The Handbook says guns "are sized by the largest rivet size continuously driven with size often based on the Chicago Pneumatic Company's old 'X' series", and gives the working rule: a 4X for normal work, the less powerful 3X for smaller rivets in thinner structure, 7X for large rivets in thicker structures.
The test is time, not force. "A rivet gun should upset a rivet in 1 to 3 seconds." Longer than about three seconds and the rivet work-hardens before the head is formed. That is the symptom of a gun that is too light. A gun that is too powerful "is hard to control and may damage the work".
Slow-hitting guns are the norm. The Handbook puts the common type at 900 to 2,500 blows per minute: slow enough to control, heavy enough to do the job. Every gun in the table falls in or just above that range, and blow rate drops as the X number rises.
Set the power on wood. Guns run on 90 to 100 psi. The driving force is set with the needle valve on the handle, tested against a block of wood and never against anything harder. If no setting gives a good rivet, the Handbook's answer is a different size of gun, not more adjustment.
What the listings add
A 2X is not a 2X everywhere. The ACAT 2X and the ATS Pro 2X list the same 2,580 BPM and 2 1/4" stroke, yet ACAT rates its gun to 5/32" aluminum and ATS rates its own to 1/8". Same pattern of gun, different claim. Treat rated capacity as the upper edge, and size for the rivet you drive most.
The X number does not always rank. Yardstore rates the ACAT 9X to 5/16" and the 7X to 3/8", with the 7X hitting slower. Read the capacity, not the label.
Shank decides which sets fit. 2X to 4X guns take .401" shank rivet sets; the 5X, 7X and 9X take .498". The ACAT corner gun takes short-shank sets only, so standard sets do not fit it.
Stroke is what separates guns of one size. The three Sioux 270A models run from a 2" to a 4" stroke; the longer the stroke, the fewer and heavier the blows.
Questions people actually ask
3X or 4X rivet gun?
The FAA Handbook names the 4X for normal work and the 3X for smaller rivets in thinner structure. In the listings, 3X guns are rated to 3/16" aluminum rivets and 4X guns to 1/4". If most of your rivets are 3/32" and 1/8" in thin skin, that is the 3X case; if you drive 3/16" regularly, it is the 4X.
What do the X's mean on a rivet gun?
They come from the Chicago Pneumatic Company's old X series, which sized guns by the largest rivet driven continuously. A higher number means a longer stroke and heavier, slower blows. It is not a count of anything.
What regulator setting should a rivet gun be at?
Neither FAA source gives a number. The Handbook says guns operate on 90 to 100 psi supply, and that the driving force is adjusted with the needle valve on the handle, tested on a block of wood, to a setting that upsets the rivet in 1 to 3 seconds.
What size air compressor does a rivet gun need?
Few listings state air consumption. The ATS 2602A lists 3 CFM at 90 psi. An angle drill asks far more: the Sioux 90° drill lists 21 CFM. Size the compressor for the hungriest tool on the line, which is usually not the rivet gun.
Can one gun do everything?
Only across neighbouring sizes. The Handbook's point is that a gun too light work-hardens the rivet and one too heavy damages the work, so a shop that drives both 3/32" and 1/4" rivets ends up with two guns.
Limits of this guide
A comparison of published figures and FAA guidance.
- No gun was tested. Trigger feel, balance and durability are what separate these guns in use, and none of that is in a listing.
- Rated capacity is a claim. Two makers rate the same size of gun differently, as the 2X row shows.
- Listings change. Figures were read on the dates shown on each product page; the seller's live page is the current one.
- The repair data decides the rivet. Which rivet, and so which gun, comes from the SRM or drawing.
Sources
- FAA-H-8083-31, AMT Handbook — Airframe, Volume 1, Chapter 4 — pp. 4-37 to 4-38, "Pneumatic Rivet Gun": sizing by the X series, 900–2,500 BPM, 90–100 psi, the 1-to-3-second rule, adjustment on a wood block.
- Seller listings — every figure in the table, via the linked product pages: Yardstore (ACAT) and LAS Aerospace (ATS, Sioux).