can a different upper effect trigger pull?

[Battering ram NIB]

ive shot 2 uppers now w/ my Mac 10

Amp 10 and a sidecocker......i have not shot my factory upper

i dont remember having a heavy trigger when shooting the amp 10, but the sidecocker was horribly heavy....so heavy id guess 15lbs.....i checked several times to make sure the safety wasnt on it was so heavy.......i dont know how a upper would effect trigger pull.....but im new to the Mac 10

thanks

 

[LawBob]

The barrel position could be slightly lower. The sear could be rubbing on the barrel in the u-shaped cupping. That would make it very tough for it to toggle. Increasing trigger pull.

 

[wtrski76]

Sear angle?

 

[sniperdoc]

Absolutely!
This phenomenon is not limited to MACs.
An old gunsmith trick is to swap parts from the bins to get the best trigger pull before stoning anything. Saves a ton of time!

 

[Battering ram NIB]

The barrel position could be slightly lower. The sear could be rubbing on the barrel in the u-shaped cupping. That would make it very tough for it to toggle. Increasing trigger pull.

i found another post about this issue....it talked about making a mark on the barrel....my barrel has no marks on it from shooting today

it was very odd....first off the side cocker would flop back and forth...which i thought it was meant to stay forward after you pulled it back to cock and pushed it forward (i didnt get the spring loaded model-found out about it too late).....then sometimes the gun would just stop...bolt wide open....i would then cock it again and move the bolt back 1/2" or so and then the trigger would go again....one time it didnt and i found the reason was the trigger pull was even more heavy.......ive got plumber forearms...i have a grip that can crush hands if i want.....and i had trouble pulling the trigger....my 12 year old couldnt do it at all....

should i send the upper back? i dont want to send my lower w/ it though....i may put my factory bolt into the upper next time....i wanted to keep my upper NIB, and basically be my spare parts kit....but its worth a test i guess....if it works then i know its the bolt

 

[root]

Who made you MAC?

I ask because I had the same problems with USGI GG mags as you. But never a problem with any upper at all.
I have a PS gun from 1972.

FI may put my actory bolt into the upper next time....i wanted to keep my upper NIB, and basically be my spare parts kit

it's this ^^^ or fork out more loot for another bolt. swaping the bolt is going to be the quickest fix since you have one on hand to test with.
stick it in and dry fire the gun see how the pull is.

Rich

 

[ChuckB]

Uppers can absolutely make a difference. It is probably simply the spring pressure, but I noticed a huge difference between the .22lr upper, and the Max11K.

 

[Battering ram NIB]

i have an original mac from Ingram---early 70's

when i get my mac 10 out of jail in the Fall ill toss the factory bolt in my new upper and dry fire it.....

 

[Battering ram NIB]

another thing i found odd....when removing the upper....i tugged and pulled and it wouldnt come off....finally i pulled the bolt back.....still nothing....when i pulled the trigger the upper shot out of the lower almost out of my hands....with my amp 10 i simply pulled the upper off, no problems....just curious if this is normal to be difficult, or should it pull off no matter where the hammer is? (i installed the upper with the hammer back originally)

 

[TonyM]

Sear angle and recoil spring strength make a difference. My M11 runs about 8 lbs with the stock upper down to as low as 6.5lbs with the 22 kit.

 

[cockednlocked45]

They are all a bit different. But thats not normal... id try the oem upper. Or you could measure them to see how out of spec it is.

 

[TonyM]

just curious if this is normal to be difficult, or should it pull off no matter where the hammer is? (i installed the upper with the hammer back originally)

What hammer are we talking about here BTW? Do you mean the bolt?

 

[Battering ram NIB]

i pulled the bolt back.....the upper would come off....when i pulled the trigger the upper flew out...almost out of my hands......before pulling the trigger the upper refused to come off no matter what else i did....

does the hammer have to be back to put in and take out an upper?

 

[cockednlocked45]

If it's a machine gun there is no hammer. How much did you pay for this gun?

 

[cockednlocked45]

The BOLT should be foreword when you put your upper on. If it's semi auto the hammer needs to be cocked back

 

[ScottinTexas]

does the hammer have to be back to put in and take out an upper?

If your MAC 10 doesn't have a hammer you got ripped off.

:boohoo
:boohoo
:boohoo

 

[Battering ram NIB]

If your MAC 10 doesn't have a hammer you got ripped off.

:boohoo
:boohoo
:boohoo

ive been told the new upper is most likely not machined correctly and have contacted the supplier......

 

[ScottinTexas]

They probably forgot to machine the hammer channel in the bolt.

 

[root]

Yup ya need a MAC hammer.
contact seller and see if they just forgot to give it to you.if not ask for a partial refund.
Also make sure the number on the handle matches the number on your receiver or you might be in violation.

Rich

 

[Battering ram NIB]

manufacturer agreed to cut the upper more deeply.....also said each upper and lower need to be tuned to each other....so i guess i should expect it to work out of the box is what i got out of it...

he is being fair at this point.......agreeing to look at it and tweak it...i do not want to send him my lower at this point