Tried my RRA upper on a PCF Lower today

[Michiana]

I had someone take one of my PCF composite lowers to do a video and he told me that his Rock River Arms upper would not fit unless he did some grinding so he returned it to me. Their web site reads that they have a very tight fit built in and to install your upper you have to put the front pin in and rock the lower onto the upper until you meet resistance and they give it a smack with the palm of your hand to seat both parts. I did that and it popped right on and has a perfect fit. If anyone buys one of these lowers and encounters a fit problem don't be afraid to give it a smack, you will not break anything. No hammers, just the palm your hand giving the grip a good downward smack. Couple photos showing the fit and finish.

 

[Ziggy01]

Looks like a pretty good fit. How long have you had the PCF lower? How do you like it so far?

 

[IndyBeerman]

I had someone take one of my PCF composite lowers to do a video and he told me that his Rock River Arms upper would not fit unless he did some grinding so he returned it to me. Their web site reads that they have a very tight fit built in and to install your upper you have to put the front pin in and rock the lower onto the upper until you meet resistance and they give it a smack with the palm of your hand to seat both parts. I did that and it popped right on and has a perfect fit. If anyone buys one of these lowers and encounters a fit problem don't be afraid to give it a smack, you will not break anything. No hammers, just the palm your hand giving the grip a good downward smack. Couple photos showing the fit and finish.

So true Richard, but I also found out one little thing with my PCF Composite lower, the front pin is a pain to get through the upper if you have a non-free floated quad rail attached. I slightly beveled the edges of the pin to get it to slide in better.

I also put a little bit of lube on the upper's tang and about 2 inches away I just slapped it together, and the rear pin went in effortlessly. Because it's composite, it needs a tighter fit to maintain a proper fit so the upper will not rock left and right.

Now all I have to do is get time to shoot it some when it warms up since my shoulder is now able to handle the recoil better.

 

[Michiana]

Haven't shot mine yet

Looks like a pretty good fit. How long have you had the PCF lower? How do you like it so far?

I am keeping mine as a sample but I have had positive feedback from customers. Most people really like the feel of the trigger. People who have a hang up with composites this is not the lower for you as the only metal on it is the springs. If it is going to be used with a 22 conversion they have a trigger you can buy for about $7 that you change out with the standard trigger which might rub. You can get find them on the internet at places like GunBroker or ask your local gun store.

 

[pftraining_in]

There is no reason for an upper to fit that tight on a lower. If accuracy is the concern, the fit between the upper and lower has no effect on "accuracy" as the barrel and sights are attached to the upper as a single piece.

A lower fitting tight enough you have to force the upper onto it shows that the lower is out of spec.

The upper and lower not fitting tightly is how the gun was designed.

This was designed because of a want, not because of a need.

 

[IndyBeerman]

There is no reason for an upper to fit that tight on a lower. If accuracy is the concern, the fit between the upper and lower has no effect on "accuracy" as the barrel and sights are attached to the upper as a single piece.

A lower fitting tight enough you have to force the upper onto it shows that the lower is out of spec.

The upper and lower not fitting tightly is how the gun was designed.

This was designed because of a want, not because of a need.

Your logic is failed, a composite lower is not as rigid as a metal lower, therefore it needs to, and has to be tighter, otherwise you risk damage to the pins and lower because or any chance of movement. We're not talking about a metal lower where that is needed to take up sloppy tolerance fittings and has the extra strength to support it.

I guess you never had a composite lower in your hands, or even taken a look at Plum Crazy's web site have you?

 

[Michiana]

Not sure why this is an issue with you?

There is no reason for an upper to fit that tight on a lower. If accuracy is the concern, the fit between the upper and lower has no effect on "accuracy" as the barrel and sights are attached to the upper as a single piece. A lower fitting tight enough you have to force the upper onto it shows that the lower is out of spec. The upper and lower not fitting tightly is how the gun was designed. This was designed because of a want, not because of a need.

The purpose of the tight fit is outlined below from the manufacturer. Obviously they felt a need to design their product this way. What is happening is your metal part is fitting the composite material to itself which is not possible aluminum to aluminum; not sure why this is a bad idea? You do not have to beat the parts together, just a firm slap of your hand seats the upper to the lower.

Our lowers are designed for a tighter fit then you may be used to, unlike metallic lowers that are rigid and offer no correction in fit within milspec tolerances we engineered our lowers to take full advantage of the material by which they are made. The composite blend that form our lower allow for an 8% elongation factor allowing it to fit just about every upper out there no matter how close they do or don’t follow the military specification. The other question: Why is it so tight, while a portion of this question is answered above; let me explain this a little bit more. If you are using both metallic upper and lower halves, after time they tend to loosen up, some can fit loose out of the box, and as many of you know, several companies have produced add in parts to try and take up the slop (accuwedge comes to mind), we decided early on in the R&D process to take this problem out of the equation all together, by following the smaller end of the milspec guidelines in this area.

 

[pftraining_in]

I have not had a plastic lower in my hands and have never had a reason to look for one. What is the purpose of a plastic lower?

I would be concerned about a product that has to fit tight to reduce damage to the product, especially from a .223 caliber weapon.

How will the lower stand up to an over pressure event?

How does the lower handle extreme temperature change?

How does the lower handle all cleaning solvents?

Does the lower accept standard replacement parts?

Will the take down pin holes and the trigger group pin holes elongate over time and will it be exaggerated?

How will the lower handle malfunction drills?

Why is fit and finish important in a firearm designed for work?

I have a lower with over 5,000 rounds that has never loosened up or required any force to install an upper.

 

[JoshuaW]

I have not had a plastic lower in my hands and have never had a reason to look for one. What is the purpose of a plastic lower?

I would be concerned about a product that has to fit tight to reduce damage to the product, especially from a .223 caliber weapon.

How will the lower stand up to an over pressure event?

How does the lower handle extreme temperature change?

How does the lower handle all cleaning solvents?

Does the lower accept standard replacement parts?

Will the take down pin holes and the trigger group pin holes elongate over time and will it be exaggerated?

How will the lower handle malfunction drills?

Why is fit and finish important in a firearm designed for work?

I have a lower with over 5,000 rounds that has never loosened up or required any force to install an upper.

You act as if plastic is some horrible, unstable substance. Remember, Glocks are polymer as well.

Yes, I dont think PCF lowers are ready to be standard issue for infantry work (at least not without much further testing) and they may not be very desirable for "match grade" work, but for the rest of us? Well, that is one affordable COMPLETE lower for about the same price you would pay for a stripped lower. Yes, they are designed to handle .223 fine, and they are designed to last quite some time. I have yet to get my hands on one, but I had similar concerns when I first saw them, but after reading some reviews and experiences with them, I am confident enough to build a plinking carbine on one.

Oh, I also know a lot of people have been using them for dedicated .22 rifles, which seems like a good use for those who are scared they cant handle the pressure.

 

[BigBrian]

Where did you get your lower and how much was it. will it take standard lower parts kit if you want to build one?
And by the way, If you use GibbsBrand Lubricant, it cleans ,lubes and will not harm any plastics that I know of. Check out this website for more info if your interested.
gsr-distributing-llc.com
Thats the only stuff I will ever use from now on on all my guns. And ive used some great stuff before and theres nothing like it that works better in my opinion.
I would really like to try one of these on a build. My friend has a carbon lower on one and I dont think it would be as good as the Plum Crazy. I dont know,but people seam to like the PlumCrazys alot.

 

[Michiana]

Where did you get your lower and how much was it. will it take standard lower parts kit if you want to build one?
And by the way, If you use GibbsBrand Lubricant, it cleans ,lubes and will not harm any plastics that I know of. Check out this website for more info if your interested.
gsr-distributing-llc.com
Thats the only stuff I will ever use from now on on all my guns. And ive used some great stuff before and theres nothing like it that works better in my opinion.
I would really like to try one of these on a build. My friend has a carbon lower on one and I dont think it would be as good as the Plum Crazy. I dont know,but people seam to like the PlumCrazys alot.

This is a complete lower and includes the fire control system and a six position stock. I was told you can put another LPK in place of the one that comes with the lower but the trigger on this product is one of its selling points so I would try it first. You can find these for sale on places like Gunbroker for around $119 plus shipping to your dealer. The price, nice trigger and light weight seems to be the big selling points.

 

[JoshuaW]

Where did you get your lower and how much was it. will it take standard lower parts kit if you want to build one?
And by the way, If you use GibbsBrand Lubricant, it cleans ,lubes and will not harm any plastics that I know of. Check out this website for more info if your interested.
gsr-distributing-llc.com
Thats the only stuff I will ever use from now on on all my guns. And ive used some great stuff before and theres nothing like it that works better in my opinion.
I would really like to try one of these on a build. My friend has a carbon lower on one and I dont think it would be as good as the Plum Crazy. I dont know,but people seam to like the PlumCrazys alot.

PCF lowers are pre-assembled. Not a bad deal for $120! Im not sure what, if any, components can be swapped out, but I have heard they pretty good triggers. All second hand knowledge, but I hope to get my hands on one eventually.

 

[Saiga223]

Does anyone know if there may be any of these lowers floating around at the Indy 1500 gun show this weekend?

 

[Michiana]

Tried another upper and got same results

PCF lowers are pre-assembled. Not a bad deal for $120! Im not sure what, if any, components can be swapped out, but I have heard they pretty good triggers. All second hand knowledge, but I hope to get my hands on one eventually.

I got another RRA upper in so I put it on my Plum Crazy lower to check the fit comparing this fit to the earlier one on my personal RRA upper and both fit so close I could not get a piece of newpaper between the two surfaces. I had to use the palm of my hand to gently thump the bottom of the handle to seat the lower but on second and third reinstalls it went right on. Seems the composite material conforms itself to the metal matching surface. This photo shows the nice fit and you can look at my earlier post and compare; notice same serial number on the lower but different uppers. So far I am still impressed with these lowers and get very positive feedback from owners as to what a nice trigger it has. My guess is someone else will also be coming out with these composite lowers in the future once people get used to them. People did not fall over themselves to pick up Glocks when they were first introduced to the marketplace; some people just want metal period.