Increase trigger weight on s400 mpr?

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mongol
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Increase trigger weight on s400 mpr?

Wed Oct 30, 2019 10:25 pm

Hi,
I want to purchase a sporter air rifle with a trigger weight similar to a 22, approximately 1.2 kg. I like the looks of the s400 mpr but I've been told the max trigger weight from the factory is no more than 20 oz. Is it practical for me to install a new stronger spring to increase the trigger weight? Or is this something that only a gunsmith can do? Fwiw, I live in the States.

Regards,
Lloyd

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TenMetrePeter
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Re: Increase trigger weight on s400 mpr?

Thu Oct 31, 2019 3:17 pm

Easy to do that. Remove from stock and remove trigger guard. Under there at the front is a grub screw that adjusts trigger weight . Wind it out and replace spring with a stronger one. You might wear out the sears though.

Take side plate off to get a good look.

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mongol
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Joined: Wed Oct 30, 2019 10:17 pm

Re: Increase trigger weight on s400 mpr?

Fri Nov 01, 2019 2:29 am

Thanks for telling me how to change the spring. However, I hadn't thought of the sear wear issue until you mentioned it. I guess I'd better think about this before I try it.

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tonyc
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Re: Increase trigger weight on s400 mpr?

Fri Nov 01, 2019 8:48 pm

I'm not convinced there will be any more sear wear than with the original spring. The spring acts on the bottom sear, opposing the force applied by the trigger. So the only additional load is on the pivot pin through the bottom sear. I wouldn't have thought this is enough to cause any problems. The other sears are unaffected.

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TenMetrePeter
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Re: Increase trigger weight on s400 mpr?

Sat Nov 02, 2019 3:39 pm

Possibly not. I would be more worried about breaking it in half with that split design, and probably a stiff 2 or 3 kg load spring to get 1.2 kg on the trigger. Remember the broken top sears a couple of years ago.

Also pity to beef up a lovely crisp light trigger.

Meh, give it a try and report back here.

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Roger5
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Re: Increase trigger weight on s400 mpr?

Sat Nov 02, 2019 9:06 pm

tonyc wrote:
Fri Nov 01, 2019 8:48 pm
I'm not convinced there will be any more sear wear than with the original spring. The spring acts on the bottom sear, opposing the force applied by the trigger. So the only additional load is on the pivot pin through the bottom sear. I wouldn't have thought this is enough to cause any problems. The other sears are unaffected.
Hi Tony, the spring acts on the middle sear, and I finally got myself another TDR in .22 8-)

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tonyc
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Re: Increase trigger weight on s400 mpr?

Sat Nov 02, 2019 11:46 pm

Roger5 wrote:
Sat Nov 02, 2019 9:06 pm

Hi Tony, the spring acts on the middle sear, and I finally got myself another TDR in .22 8-)
Clash in terminology... is the lever the trigger acts on a sear? There's no break point, and any wear at point of contact is not going to affect the trigger function. Whatever, I agree with TMP, I wouldn't want to load a light crisp trigger. Even hunting I have mine on the light side of the adjustment range.

.22 TDR - original short barrel or later longer one (same as .177)?

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Roger5
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Re: Increase trigger weight on s400 mpr?

Sun Nov 03, 2019 7:59 am

Can see where your coming from, I'm only going by users handbook, TDR is same as later .177 :)

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TenMetrePeter
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Re: Increase trigger weight on s400 mpr?

Sun Nov 03, 2019 9:14 pm

Its usually known as the "three sear trigger" so by that logic they're all sears .

Could also replace the lovely MPR trigger blade with a later standard hunter trigger with the anti rattle spring beefed up.

It just sounds awful.

By the way just tead the OP again. The factory trigger is a couple of ounces max.

A better simulation of a .22 with a three pound trigger might be a chinese springer

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Raj
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Re: Increase trigger weight on s400 mpr?

Tue Nov 05, 2019 7:20 pm

Why would one need such a heavy trigger? Just an objective question ... Not saying light or heavy is better or anything. Just curious.
“It's the Indian, not the arrow"

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