Basic Marlin T-900 Trigger Job (Marlin 917V)

I just picked up a Marlin 917V, and after two shots I knew something had to be done about the trigger.  On my first attempt to shoot I actually stopped pulling because I thought the safety was on!  Regrettably, I didn’t check the weight of the original trigger, but it was 10 pounds if it was an ounce, and probably more.

Marlin 917V

New (to me) Marlin 917V

A quick internet search turned up this thread on rimfirecentral.

Following, then, is my foray into improving the Marlin trigger.  This step covers the basic (spring replacement) step.  I’ll follow up with an ‘advanced’ trigger job involving actual modification of the trigger pieces.

To start, disassemble the rifle.  Pull the bolt to the rear, while squeezing the trigger and remove the bolt.  Then remove the main action bolt, and the forward trigger guard bolt.

Action screws removed

The front trigger guard (action) and barrel screws removed.

You should now be able to lift the barreled action out of the stock.

Here’s a picture of the right side of the trigger housing.  Marlin has kindly left a hole for lubricating the sear surfaces and you can see how they mate in that window.  Note also the safety (shown in the “fire” position”).  In the “safe” position, the black sheet metal piece moves in front of the tab that is part of the rear of the trigger.  In the fire position, the tab is lined up with the slot in the safety, where it is free to move.

Trigger - right side

Right side of the trigger, note 'window' to see sear, and safety in "fire" position

Here’s the left side of the trigger.  Again you can see the window that allows visibility of the sear surfaces.  Note the two visible springs.  The vertically oriented spring at the rear of the trigger assembly is the sear spring and biases the sear into engagement with the bolt.  The angled, nearly horizontal, spring is the trigger return spring, and the subject of this discussion.  The trigger group may be removed by removing the screw holding the trigger housing to the receiver.  The sear spring is then free to fall out – don’t lose it!

Trigger, left side

Left side of trigger, note sear spring (vertical) and trigger return (angled, almost horizontal) spring.

Remove the e-clip on the pin holding the trigger, and push it out.  This releases the trigger and the trigger return spring.  The plan here is to replace the trigger return spring with something quite a bit less powerful.  (There’s no need, barring lawyers, to have such a heavy spring).  A nearly-correct spring can be found in a PaperMate FlexGrip ballpoint pen.  I cut some of the end coils of each end of the PaperMate spring to better match the length of the factory vehicle suspension spring.

Disassembled trigger

The trigger removed from the housing. The original spring and PaperMate FlexGrip Spring that will replace it.

Reassemble the trigger housing, using the PaperMate spring.  Note that the safety will have to push a little forward in order to completely seat the pin.  Replace the e-clip. The e-clips on my rifle were very light and easy to remove and replace – thank goodness for small favors!

Reassembled trigger

The reassembled, and re-installed trigger. Note position of the safety, which must be moved to clear the head of the pin when re-inserted.

After reassembly, the new trigger pull was a creepy 3lbs 10oz – a huge improvement, but still not where I want to be.

Trigger weight

The new trigger weight is just shy of 3 pounds, 10 ounces - a significant improvement.

I fired a five-shot group with this trigger into a neat little bug-hole at 25 yards.  It’s clear that the rifle has more accuracy potential than anyone would be able to squeeze out of it with the factory trigger.  I look forward to further improvements and longer range testing.

We’re not done yet!  After any trigger work it’s important to thoroughly test the trigger for safety.  This should consist of the following, as a minimum.  With an unloaded rifle:

  1. Apply the safety and pull back on the trigger – the rifle should not fire.
  2. Release the safety, having performed test #1 – the rifle should still not fire.
  3. Drop the butt of the rifle from a height of one foot, onto a padded floor (a sleeping bag pad is ideal) with the safety off.  The rifle should not fire.
  4. Vigorously exercise the bolt at least five times, with the safety off.  The rifle should not fire.

If the rifle fires in any of the tests, you have an unsafe trigger and should revisit the work done.  Performing a spring replacement will very seldom adversely affect the safe operation of the trigger, but it’s good to get into the habit of performing these tests as unintended changes, such as mis-assembly can potentially cause problems.

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