I have…a bunch…of PTR91 rifles. Many of them were manufactured before PTR started offering the paddle magazine release that was standard on original G3 rifles. For stupid ATF reasons, semi-auto G3 copies (HK91, etc.) couldn’t have the paddle release because the infrastructure of the release allowed the use of full-auto parts in the gun. Long story short: if you want the paddle release you have to install it in a way that prevents the use of full-auto parts. Most manufactures said ;screw it’ and simply omitted the paddle since the design also incorporated a magazine push-button release.
TOP: no paddle, BOTTOM: paddle. (Not to be confused with getting your bottom paddled.)
But….that release button is awkwardly located. The paddle release is the way to go. PTR finally made the paddle release a standard item on their guns and it is wonderful. Now, what about the guns that pre-date that? Well, there is a small(!) aftermarket of people who will mod your non-paddle gun to have the paddle. First in the field: Bill Springfield.
I’d been reading about his work for a few years. I contacted him and asked if he had a quantity discount. And….I just sent off a buncha PTRs for him to modify. I’ll let you know how it turns out.
The conversion is normally around $200. Since a new PTR with the paddle is around $1050-1100, and most of my PTR’s were acquired in the $600 range, it makes more economical sense to have the conversion done.
The G3 platform suffered from a couple issues that keep it from being an awesome platform, but all those issues can be mitigated nowadays.
The DPMS pattern AR10s are very good. JP Rifles is top notch as is Seekins Precision. Adams Arms puts out an op rod AR10.
Aero Precision is also top tier.
Live Free Armory makes some propriety receivers, but they accept the DPMS pattern PMAGS. they have an accuracy guarantee claim. They are a tad lighter.
One problem that still exists is the proprietary parts, and not knowing for sure if it fits your specific AR-10 type rifle till you get the parts. Most manufacturers don’t have much, in the way of spare parts in stock, so you have to go to other venders to stock up. I’ll stick with my “91’s”, with their readily available and cheap parts and mags, and their “Mad Max” reliability.
I’ve got two Armalite AR-10’s (different vintages) and it’s a PITA to find mags that fit. They both seem to take the modified M14 mags, even though one of them isn’t supposed to. And though there are guides out there that tell you which series takes what, I find they aren’t always right. Which is why I have a box full of brand new mags still in the packaging that I can’t use.