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Work order — Ithaca Model 37

Taking the firearm apart for a job such as refinishing, and putting it back together to specification. Generated from the Pew-Takedown entry last updated 2026-10-29. Confidence: medium.

Shop difficulty: Tier 2 of 3

Roughly 60-80 key-numbered parts on a bottom-eject pump whose breechblock, slide and carrier must be stacked in the hand and slid in as one group while the spring shell stop is pried aside, then the carrier screws started together and the slide pin re-engaged. A strongly sprung top extractor plunger and a trigger plate that binds unless the stock is loosened add to it, but nothing is timed. 80 parts (Highest schematic key number in Ithaca Gun Co.'s own parts store (internal-parts pages, keys 04-80 seen; 01-03 not offered). Includes variant and accessory keys (DeerSlayer sights, scope bases, swivel). Pew-Takedown's rating, not the manufacturer's.

Bench time: strip ~55 min, rebuild ~85 min (estimate). Actual: strip ______ rebuild ______

Special tools:

• Thin punch — Compressing the top extractor plunger
• Small pry tool — Easing the spring shell stop aside for the slide lug
• Well-fitted long screwdriver — Stock bolt without splitting the thin wrist

Watch for:

• Breechblock, slide and carrier have to be assembled in the hand in a set relationship and slid into the receiver together; the group stops against the spring shell stop, which must be pried out with a small tool to let the slide lug pass. (reassembly; War Department)
• The two carrier screws must both be started before either is tightened, and each pin end must enter the carrier; with only one seated the carrier is bent sideways and misses the shell stop. (reassembly; Accurate Reloading Gunsmithing Forum)
• The top extractor is held by a powerful spring plunger that must be pushed back with a thin punch while the extractor is worked out or in. (both; Shooting with Hobie (blog))
• The trigger plate group will not go back far enough for its through-screw unless the buttstock bolt is loosened first, and the thin wrist around the stock screw splits if the screwdriver wedges; a loose steel washer must not be lost. (both; Canadian Gun Nutz)

1. Clear and make safe

1. Point the muzzle in a safe direction and keep your finger off the trigger.
2. Engage the safety.
3. Press the action release and pull the forend rearward to open the action.
4. Cycle the action repeatedly, catching each shell as it drops from the bottom port, until no more feed.
5. With the action open, look up through the bottom port with a light to inspect the chamber and the magazine tube.
   Warning: There is no side port. The bottom port is the only way in — use a light and take the time.
6. Physically confirm the chamber is empty and remove all live ammunition from the work area.

2. Disassemble

Field Strip

1. Complete the Clear and Make Safe procedure.
2. With the action closed, depress the magazine cap detent and unscrew the magazine cap.
3. Rotate the barrel and withdraw it forward out of the receiver.
   Tip: The Model 37 barrel is an interrupted-thread fit rather than a simple slip-on — rotate it as you pull.
4. Withdraw the forend, action slide, and bolt assembly forward out of the receiver.
5. Push out the trigger group retaining pin and lift the trigger group out through the bottom of the receiver.

Remove the stock and trigger plate group

1. Remove the butt plate screws and the butt plate.
2. With a long-shanked screwdriver, unscrew the stock bolt from the hole in the butt of the stock.
   Tip: The stock bolt has a square head; if it is tight a 3/8-inch socket wrench may be used.
3. Pull the stock to the rear off the tang of the receiver.
4. With the hammer in the forward (fired) position, unscrew the trigger plate screw from the left rear face of the receiver, just above the trigger.
5. Pull the trigger plate group to the rear out of the receiver.

Remove the breechblock, slide and carrier group

1. Remove the barrel and the trigger plate group first.
2. Hold the receiver bottom side up with the magazine facing left.
3. With a fingernail or small flat instrument, pull the slide pin (visible in the forward end of the slide) toward you while moving the slide handle forward, until the slide bar is released from the slide.
4. Unscrew the two carrier screw locking screws in the right and left walls of the receiver.
5. Remove the two carrier screws.
6. Pull the carrier, breechblock and slide together out of the rear of the receiver.
7. Remove the positive shell stop from its groove by pushing inward on its pivot stud where it projects through the right wall of the receiver.
   Tip: The manual removes it here to prevent its loss.

3. Refinish

The components the procedures above separate. Coating, masking and cure are outside this database; follow your coating system's instructions. A part the manufacturer marks "factory fit" should not be swapped or reworked.

The manufacturer's full parts list (24 parts) is on the reference page.

4. Reassemble

Remove the breechblock, slide and carrier group

1. Reverse the steps of "Remove the breechblock, slide and carrier group".

Remove the stock and trigger plate group

1. Reverse the steps of "Remove the stock and trigger plate group".

Replace the breechblock, slide and carrier group

1. Clean, lightly oil and lubricate the parts before replacing them.
2. Replace the positive shell stop in its groove in the inner right wall of the receiver, thin curved end forward, so it lies flush with its pivot stud flush with the outer right face of the receiver.
3. Hold the breechblock bottom side up, extractor to the left, in your left hand.
4. Place the slide on the breechblock so the hook-shaped aperture in the rear of the slide mates with the hook-shaped lug on the rear of the breechblock.
5. Take the carrier in your right hand, long points to the left and curved notched end up, and slide it onto the breechblock from the rear so the breechblock lies between the carrier's long ends with the slide above it and the small lug on the rear of the slide fits the notch in the rear of the carrier.
6. Transfer the group to your right hand and take the receiver in your left, bottom side up and open end to the right.
7. Slide the group into the receiver through the open end, long ends of the carrier first, so the guides on the slide mate with the guideways in the receiver walls, and push it in until the slide is checked by the rear end of the spring (left) shell stop.
8. Depress the forward end of the spring shell stop, insert a small tool under its rear end and pry it out slightly from the receiver wall until the lug on the slide will pass under it.
   Warning: Do not pry the stop out farther than necessary.
9. Push the group all the way forward.
10. Move the carrier to the rear until the carrier screw holes in carrier and receiver line up.
11. Insert both carrier screws and catch the threads on both before screwing down either.
    Tip: The pin end of the carrier screw must enter the carrier before its thread will mate with the thread in the receiver.
12. Screw the carrier screws in snugly until the locking-screw countersinks in their heads line up with those in the receiver.
13. Replace the locking screws and draw them down snugly and flush.
14. With the slide forward, move the slide handle to the rear until the bar contacts the slide pin.
15. Retract the slide pin (visible in the bottom of the slide) with a fingernail or small flat instrument, move the bar rearward until the pin engages the hole in the rear end of the bar, and release the pin.
16. Operate the slide handle to test the operation of the slide and the locking of the breechblock.

Replace the trigger plate group and stock

1. With the hammer forward and the slide forward, push the trigger plate group into the lower rear end of the receiver, hammer first, so the guides on the plate mate with the guideways in the receiver walls.
   Tip: With the hammer forward the slide stop will not interfere with the slide; if the hammer is cocked, the slide stop must be held disengaged.
2. Push the plate forward until the screw holes in plate and receiver line up.
3. Replace the trigger plate screw from the left side of the receiver and screw it in snugly until its head is flush with the face of the receiver.
4. Slide the stock on over the receiver tang until it is flush with the rear end of the receiver and trigger plate.
5. Replace the stock bolt and washer and screw down tightly, turning clockwise.
6. Replace the butt plate and screw it down snugly.
   Warning: Butt plate screws turned too tight may strip the threads in the stock or crack a composition butt plate.

Reassembly

1. Install the trigger group into the receiver and insert its retaining pin.
2. Feed the bolt and action slide assembly into the receiver from the front, keeping the action bar in its track.
3. Insert the barrel into the receiver and rotate it to engage the interrupted threads.
   Warning: Seat the barrel fully. A partially engaged barrel will not headspace correctly.
4. Thread the magazine cap on and tighten it until the detent engages.
   Warning: Confirm the cap is fully seated and the detent has clicked.
5. Cycle the action several times and perform the function check.

5. Torque

No manufacturer torque values are recorded for this firearm.

Notes: The manufacturer's documents give no torque value. They say: "With a small screwdriver screw in the yoke screw, but be sure not to over tighten it (Figure 23)." (Ithaca Model 37 Owner's Manual, PDF p. 14) "Once the barrel is seated, center the yoke to the barrel and snug the screw but do not tighten." (Ithaca Gun Co. FAQ)

Fit or check on rebuild

• Both carrier screws seated in the carrier — With one screw off its hole the carrier is bent and misses the shell stop.
• Slide stop and lock-up test — TM 9-285 has the slide reciprocated and lock-up tested after replacement.
• Function check: safety, trigger/sear release, disconnector and feeding with dummy rounds — Standard after any detail strip; a mis-assembled sear or disconnector can double or fail to fire.

6. Function check

• Verify the shotgun is unloaded — chamber and magazine tube — before each step.
• Cycle the action fully. It should run smoothly without binding and lock closed.
• With the action closed and the hammer cocked, engage the safety and press the trigger. The hammer must not fall.
• Disengage the safety and press the trigger. The hammer should fall.
• With the hammer down, confirm the action will not open until the action release is pressed.
• Load two dummy shells into the magazine and confirm they feed and eject cleanly, one per cycle.
• Determine whether your gun has a trigger disconnector: with the hammer cocked and the trigger held to the rear, cycle the action fully. If the hammer falls as the action closes, the gun slam fires and has no disconnector.
• Know the answer before you load it. A slam-firing shotgun handled as if it has a disconnector is dangerous.

If any check fails, the firearm is not safe to fire. Stop and see a licensed gunsmith.

Sources

1. Ithaca Model 37 Owner’s Manual — Ithaca Gun Company primary
2. Ithaca Model 37 Owner's Manual — Ithaca Gun Company primary
   https://ithacagun.com/wp-content/uploads/2017/09/OwnersManualM37.pdf
3. Ithaca Gun Co. FAQ — Ithaca Gun Company primary
   https://ithacagun.com/resources/faq/
4. TM 9-285, Shotguns, All Types — War Department primary
   https://archive.org/download/TM9-285/TM9-285.pdf
5. Ithaca Model 37 Featherlight | Ithaca Gun Co — Description / Additional information — Ithaca Gun Company primary
   https://ithacagun.com/product/model-37-featherlight/
6. Internal Parts (product category, page 4) — Ithaca Gun Company primary
   https://ithacagun.com/product-category/parts/internal-parts/page/4/
7. Ithaca Model 37 ejection problem — Accurate Reloading Gunsmithing Forum anecdotal
   https://forums.accuratereloading.com/eve/forums/a/tpc/f/9411043/m/522105431
8. Ithaca M37 Riot Shotgun (blog post with keyed disassembly notes) — Shooting with Hobie (blog) anecdotal
   https://shootingwithhobie.blogspot.com/2008/10/?m=0
9. Ithaca 37 Shotgun Taking out the trigger assembly? — Canadian Gun Nutz anecdotal
   https://www.canadiangunnutz.com/forum/threads/ithaca-37-shotgun-taking-out-the-trigger-assembly.529626

Educational guide only. Some information comes from non-authoritative sources. Always consult your manufacturer's manual and a licensed gunsmith. Verify your firearm is unloaded before every procedure. Full disclaimer: https://github.com/Fundamental-build-LLC/Pew-Takedown

Legal notice: this material is third-party information compiled from sources of varying reliability and is provided for general informational and educational purposes only. It is not gunsmithing, technical, safety or legal advice, it is not verified or endorsed by any manufacturer, and it must not be taken as fact. Any work on a firearm beyond the routine field stripping described in its own owner's manual should be performed only by a licensed and insured gunsmith. You use this material entirely at your own risk. Fundamental Build LLC and the project's contributors make no warranty of any kind and accept no liability for death, injury, damage or loss arising from its use. Full terms: LEGAL.md.