Gunboards Forums banner
1 - 6 of 6 Posts

·
Registered
Joined
·
36 Posts
Discussion Starter · #1 ·
I have been watching and re-watching this video which shows how the trigger and bolt mechanisms work on the T99.
HOW TYPE 99 ARISAKA WORKS

I think that I understand how the bolt cocks the firing mechanism on closing of the bolt, and I think I understand how the trigger pull will cause the sear to disengage the firing pin and that allows the rifle to fire. I see the parts of the trigger, and how they seem to work during the cocking and firing steps. I don't see what it is that makes the trigger pull so hard, but my rifle definitely requires a good "pull" on the trigger to get it to fire, rather than a gentle squeeze. I did see one video online where a guy shims something under the trigger to loosen the firing. I think he did it with a sliver of metal cut from an aluminum soda pop can. I could not tell from his video where he actually puts the shim, but I think from watching the video I linked to above that I can sort of see where that might be.

But anyway, what is it that makes the trigger pull so bad on these rifles? I shoot mine enough that I have kind of come to adapt to the trigger and can sort of overcome the issue, but I do wonder what is it about the mechanism that causes the harder pull?
 

·
Registered
Joined
·
1,075 Posts
Maybe the shim you speak of is between the firing pin catch and sear. If those surfaces are boogered up with ridges/burrs, the friction can be harder to overcome. Personally, I would not mess with those surfaces...last thing one needs is a firing pin to drop before bolt locks up. Bad day for whoever is holding onto the bolt and the face and neck behind it.
 

·
Registered
Joined
·
36 Posts
Discussion Starter · #4 · (Edited)
This is the video where the guy installed a shim. I can't tell where he actually put it, or what it is doing. I would not do this for many reasons, nor would I file those parts he did the filing on. But, this what he did:
WWII Type99 Arisaka Trigger Adjustment

Also, from other reading and investigating, it sounds like at least some of the amount of trigger pull needed to fire the rifle is due to the trigger return spring (I think that is technically called the sear spring). I am not willing to mess around with that, or any other parts of the mechanism of my nice rifle which works well for me but just has a harder trigger pull than I would prefer. Except for the no-drill, no-tap S&K scout scope mount I put on, this rifle is as-issued.
 

·
Registered
Joined
·
8,574 Posts
Well my thoughts are it's a military rifle not a "Camp Perry" match rifle. It's design needs a trigger to withstand all the rigors of combat use. Rough handing, being dropped, possible snagging the trigger on underbrush etc. I think you get the idea. If it bothers you get some polishing compound and polish the mating surfaces. Just don't change the geometry of the parts.
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top