Glock 34 3rd Gen lower with G35 g4 upper

[FLHX 1]

I have a g34 g3 and a G35 g4.  I want to get the G3 grip reduced and stippled. The question I have can I then use the G35 g4 upper on the G3 lower and visa versa - use the Gen3 upper on the Gen 4 lower.

 

I am trying to avoid doing any changes to the gen 4 lower until I have shot it for awhile. I want to use the g35 in limited but i also want to be able to use the g34 still in production so that would mean using the g4 lower from the 35 on the 34 upper in prod.

 

I also have read that some of the Zev triggers will no work like the Gen3 parts as the Gen 3 9mm and 40SW lower parts were the same, I don't think so with the Gen4.  I should of just got a Gen 3 35 and I wouldn't have these issues.

 

I hope whoever reads this can understand what I am saying as the more I research this the more confused I get.

 

Any help would be appreciated!!

[Russell 3]

You cannot put a Gen 4 upper on a Gen 3 lower and vice versa. Look at the front of the dust covers, the Gen 4 is more open to clear the dual recoil spring. The area inside the frame where the back of the recoil spring assembly touches might also be different, but I don't have them in front of me right now.

 

If you just stipple the G34 and don't also get a grip reduction you can still use it in production as long as you keep the stippling within the area noted in the rule book. Also, technically even if you could swap uppers I don't think that would be production legal. I believe the gun has to be in the original caliber so if using a G35 lower would have to be .40, not that anyone would be able to tell.

 

I'm not sure about the Zev trigger.

[AdamM 42]

You can put a gen 3 upper on a gen 4 lower, but not the opposite. There will be a little more gap with the 3 upper on the 4 lower, but functions just fine.

[FLHX 1]

Ok thanks for the replies. I just want to add one more question. Is a GEN3 35 upper compatible with a GEN 3 34 lower? I think I know the answer but I need to be sure before I make a decision.

[AdamM 42]

I cannot say for sure by my "guess" is that it would work just fine.  You can contact Lone Wolf as they would probably know for sure.  http://www.lonewolfdist.com/Products.aspx?CAT=244

 

They show the G34/G35 as being the same "series" of slides.  I have their Long Slide gen 3 (they only make gen 3 slides) on my gen 4 G21 and it works great.

[Russell 3]

I hadn't tried it previously, but it looks like Adam's right and a Gen 3 upper will work on a Gen 4 lower.  There's a gap around the front of the slide, see below picture, but I don't see why this wouldn't function ok.  I didn't try firing it like this, just put the slide on and it seems to work fine.  It definitely would not work going the other direction with a Gen 4 upper on a Gen 3 lower.

 

A 34 and 35 lower of the same generation are identical except for the ejector.  A 9mm slide will likely work fine with a .40 ejector (lots of folks do it with conversion barrels).  However, I've heard that you should NOT use a 9mm ejector when shooting .40.  There's a possibility that the 9mm ejector could hit the .40 primer and set it off when ejecting a live round.  I don't know if there's been a confirmed case of this, just a rumor I've heard, but I wouldn't risk it.  It's very easy to swap ejectors.

 

Keep in mind rule 21.3 if you're still planning on using this for Production.  A 9mm upper is not allowed on a .40 frame.