I’m thinking from a PDW point of view, when you are trying to have the smallest overall package, inserting the mag in the pistol grip would be best, like on a MP7 or TP9. But then there’s PDW’s like the CZ Scorpion or B&T GHM9 that serve the same purpose but it sets up more like a rifle with the mag well in front of the grip thus creating a bigger overall gun. So other than overall length, what are the pros/cons to having the mag well inside the grip vs. out in front? Thanks all!

Longer barrel per overall length when mag is in the grip like a pistol. This requires the makes to conform to a pistol style grip for ergonomacs

Pistol mags don’t necessarily make the best sub gun mags though, so it depends on what you are after

Not much of a contribution but I held an Uzi last weekend and the grip is very thick and uncomfortable.

A bullpup design can have the magazine even further back than the grip. If you want a magazine in the grip it really just requires the cartridge to be short enough to fit there. Longer cartridges must go either in front of or behind the grip. But it’s the same concept whether in the grip or behind it—a trigger bar connects the trigger to the hammer or striker rather than a direct linkage.

The magazine can also go on the top like in the famous FN P90, which I believe is the gun/cartridge that coined the name PDW. The oldest and still most successful military design is the magazine in front of the grip, as in the AR and AK, because it offers superior ergonomics, which we can only conclude means ergonomics trump overall length in form and function.

Biggest con to a pistol grip mag is length of cartridge.  Longest stuff folks have stuffed in there are things like .30 Carbine, 5.7x28mm, so there's a practical limit to what the average human hand can hold.

As far as bbl length, you can always go bullpup, and put the magwell behind the pistol grip.

I run both types in a lot of PCCs.

IMHO the forward mag layout is usually more familiar for most of us. Easiest to train for fast mag changes.

Grip magwell layout allows for a shorter overall length, nice if running a 16” barrel. For 8” or less barrel length then it gets tight in the foregrip area.

I run a Glock g32 in a micro roni stab brace and it’s a VERY compact hold.

I guess the other big difference would be a magwell grip has to use a pistol mag like a CX4 carbine or a Sub2K while a mag forward can be either a pistol mag or a dedicated mag like an Evo Scorpion or MP5.

And this may be coincidence but it seems the triggers in my mag forward pccs are better on average.

You put the mag well where it fits in the overall length of the action.

Some think bullpups work well until - you change out the mag, which is buried under your arm and relatively inaccessible by EITHER hand. With the mag well in the pistol grip it's literally neutral but the OAL of the cartridge is limited. In front of the grip the off hand can manipulate it while the finger remains on the trigger - same as in the grip - but a much larger OAL can be used.

Bullpups have been out for how long? Steyr AUG? How well do they place in 3Gun, they try everything to win, including weird things like .30x45 wildcats to meet an early .30 mandated caliber. Which became .300 Whisper. Which became .300BO. Which still hasn't won a 3Gun championship, even tho it's been around longer than bullpups in modern inventories. And nobody wins with bullpups.

Simple fact, mag in front has the best accessibility, works with EFFECTIVE cartridges, and is the least worst choice. Don't forget - you could put it on top like a Bren MG - our out the side like the MP38 or 40, but no, those fads passed. It goes in front. Sorry your "girl" lost.

Gun design works like this: you calculate what you want the bullet to do, which is carry X amount of power to X meters of range.  That determines the powder capacity, and the engineering of feeding a round of that caliber of barrel limits the overall configuration and shape. There's your effective round, it's overall length, and you figure out how many you need, which is now usually stacked on a combat weapon for more capacity. From there the mag goes directly behind the chamber for the simplest, least malfunctional dynamics, that determines the receiver, and magazine design is more important than what fashion of grip shape is popular this month. After 110 years of experimentation, the mag goes forward, then trigger, requiring grip behind it and all under the receiver. You really don't have unlimited ways to fool with things as every change from that recipe means discarding a proven dynamic functional relationship to screw around with trying to find how your special version's performance envelope is defined. You spend money and time discovering how to make it work when you could just as well left enough alone to get what is proven in the field years earlier.

What was pursued in bullpups was a work around for a stale cartridge development cycle were old WWII based designs were being forced into use in new modern battle spaces, and you can't stuff a .30 into an armored personell carrier or HMMV as easily as we like - unless you shove the whole receiver down the stock to accept the mag under your arm, and you still plan on carrying half the ammo and pretending your soldiers can hit a target in the field trying to hide and manuever 500m away. We'd already discovered that no, soldiers will not do that, only shoot if they can see the enemy, and most aimed fire takes place out to 125m. And we had been doing that since before WWI. It was the OTHER combat arms who were devasting the ranks, with artillery, airborne bombs, mortars, and the advent of the machinegun against lines of advancing troops was another annihilator.

Making the mag harder to change in order to stuff it into a truck was no improvement. Making the cartridge easier to fire - recoil - and being able to carry more - 2 X more - and having the whole weapon configured with ergonomic controls which fell under the working hand and fingers - unlike many combat rifles - and you get what we have been using longer in history than any other weapon, short of the flintlock.

Pistol ammo won't reach out to 125 EFFECTIVELY, and hiding the mag behind the grip doesn't make it a better idea. Time to suck it up and admit, the AR pattern does a lot of things right, and it's why so much of the new combat rifle designs copy it. It did to combat rifles what roof prism design did to porro prism binoculars. It brought in the final upgrade and since then it's mostly been finessing materials and finishes, with a few sidetracks adjusting the cartridge, many of which have disadvantages. 6.x mm has it's place - but to use it we really have to completely accommodate a cartridge which does it all right, and make one final adjustment. Regardless - the mag goes in front of the trigger which has a grip behind it.

Don't forget, not one screw in the design is the ultimate goal, as there would be  no tool ever needed for field stripping or repair.

MP7, MP9 are PDWs, while CZ Scorpion, B&T GHM9 are SMGs.

PDWs are more concerned with concealability.  Of the four, only the MP7 and MP9 are holsterable, with the MP9 having more options (high ride, mid ride, and thigh ride).

MP5K came close to holsterable, but it is slung, rather than holstered.

Small nitpick - the MP 48 & 40 put the magazine in front of the trigger on the bottom of the receiver.  You're thinking of the MP 18/28, Lanchester, STEN, Sterling, and the Luftwaffe's FG 42.

I'm building an upside down long bbl AR as a gift and something to play around w/, so we'll see how convenient top feed is.  I've long wondered about an angled top-fed bullpup.

One of the commonly stated advantages of the grip magwell is that it provides "hand finds hand" reloading which some consider more ergonomic.

I sort of like the top fed mag like the P90 or Calico pistols/ carbines. Bottom eject is great for ambidextrous use.

what are the pros/cons to having the mag well inside the grip vs. out in front?

Think for a second.....

It's dark and you need to reload your pistol.  Grab a magazine from your belt.  Hand finds hand.....it's intuitive.

Aloha, Mark

Biggest advantage with mag well in the grip would be in a quick reload. Hand goes to hand, no need to look for the mag well.

this...

If you can't locate a magazine well in front of the grip (or behind for a bullpup) without looking, you need more practice. Not saying that you'll set reload records without being able to keep eyes on the magazine well, but it is something you should be able to perform without much trouble.

How does your hand find the mag, though?  *mind blown*

Or the charging handle or whatever else you need.  It's an overblown concept that mostly derives from competition where there are lots of timed mag changes (same as 'riding the reset' in handguns)

Concealment due to shorter length for mag-in-grip guns. From a design standpoint, you can make a more reliably feeding magazine if you aren’t shoehorned into fitting a human hand, and can instead have as much curve as needed for consistent feed. Look at early vs modern MP5 mags. Curving the mag adds cost and difficulty in manufacture, so they didn’t do it for fun, but for reliability.

Top feed mag on a bipod mounted LMG like the Bren makes much more sense than bottom mounted......

If you're top feeding, you're already 2/3 of the way to a belt fed architecture, and for an LMG it makes even more sense to go that route (belt-fed BREN is more or less what the UK59 is, granted the bolt locking scheme is slightly different)

The upward-canted side-magazine arrangement of the ZK383 is actually pretty nice, too.  It still tosses cases to the side and has a lower profile, yet still offers plenty of access for swapping mags.  Low enough that it doesn't block much of the shooter's view like the BREN mag does, either.  You can probably get even lower since the cases don't need clearance under the gun to eject.

After using the RDB in competition, the biggest hurdle for bullpups is making sure the sling isn't blocking the magwell when you bring the gun up.  They occupy the 'same space' along the length of the gun so it can be an issue.  They also trimmed away so much of the magwell on this particular gun that the mag really needs to be lined up right to go in, so now I understand the appeal of that bolt-on magwell funnel they are now selling (not that I'll be getting one)

Agreed.  The whole "hands finds hands" is a an excuse for poor training.  Even with that that mindset, you still have to practice those no-look magazine changes which includes accessing your spare magazine...there's no hand on your hip to help guide you.  It simply takes a lot of practice and drills to do no-peeking magazine changes; location of the magazine on the gun is no different than the location of your spare magazine.  Hands finds hands is a nice marketing scheme...how many speed guys need funneled mag wells?  Hands finds hands isn't fool proof; it still takes practice regardless of where the magazine is seated or where the spare is located on your body.

Size (likely weight as well) and limitations to pistol calibers are likely the biggest advantage(s)/disadvantage to having the magazine in the grip vice out front.  Some could argue for sight radius on the front-magwell versions, but with mini RDS options, that point is really moot.

Oh, and I find 9mm quite effective out to 125 meters.  It definitely won't have the energy of a rifle round, but a PDW/compact PCC that can accurately and quickly put rounds on target are quite viable weapons out to that distance.  Personally, I find them excellent inside 100 meters, but I've done enough drills to reach out to 150 meters that I'm comfortable with the accuracy of multiple shots...I'll let the target worry and debate about terminal effects.

ROCK6