[SFRC] Derya Pump-Action Lineup | DYPA-12 9mm, DYPA-16 9mm & TM22 PA-18 .22 LR | New Stock | TheAmmoSource.com

[Stevo]

Thank you for the detailed report, much appreciated! The next best thing to original Glock mags are the Magpul Pmags for Glock pistols. They have a reputation of feeding just as reliably and cost a bit less.

As for the insertion issues, the Glock mags have a cutout into which the mag catch protrusion is supposed to "snap in". Hence why you can insert a Glock mag into a Glock pistol with the slide open and never have an issue. The mag makes an audible "click!" when it is fully seated. I would assume that the problem is there : the Derya needs to copy the Glock mag catch in order to be 100% reliable with the bolt open or closed.

With any luck, it is perhaps just a matter of proper fitting (filing or sanding) to make it work more smoothly. It is possible that the mag catch is just poorly cast and doesn't fit into the mag cutout very well. Perhaps the mags' cutouts are not made or positioned properly on the magazines themselves. Or perhaps the mag catch spring is too weak and doesn't engage strong enough...? Impossible to tell without taking the firearm apart and doing an in-depth inspection / function test.


I generally hate buying a project gun right out of the box, but this puppy sure looks like it's worth a bit of tinkering with!

The square shoulder on either side of the mag is the over-insertion stop on the Glock mag, not the mag catch.

If the Derya mag well isn't shaped the same as the Glock, the over-insertion stops don't do anything.

 

[762mm]

The square shoulder on either side of the mag is the over-insertion stop on the Glock mag, not the mag catch.

If the Derya mag well isn't shaped the same as the Glock, the over-insertion stops don't do anything.

I see, thanks for the clarification.

I'll have to compare the Derya mag well to my G17, once I receive it.

.

 

[machone]

Got mine today. Pretty accurate. Mag seating issues with pmags.

My kid asked what it was. I told him it's a derya dypa. He says back "they called the gun a diarrhea diaper?!"

And I can't unhear that.

 

[FrancoisG3784]

By the disassembly diagram (I can't clearly see the parts diagram), there's a recess on the underside of the bolt that is doubtless for a locking wedge, like on a Marlin lever or similar.

That being said I don't like the idea of a pump gun that doesn't have an in battery lock. I certainly would not buy a shotgun, or even a rimfire, that pumps freely in any state - that's pretty basic stuff.

It does have an in battery lock, you just said it has a locking wedge, it’s no different than a tilting bolt like on a Savage 99 lever action for example, pulling the pump all the way forward locks the bolt in battery and it stays locked until you pull the pump back. The SKS as another example uses a tilting bolt and it only unlocks when the piston smacks the carrier which then moves back lifting the bolt into the unlocked position, if you took the gas piston out of the SKS it would become essentially a straight pull and pulling the charging handle back is what moves the carrier then unlocking the bolt, so the bolt on the Derya won’t unlock until you pull the pump back. The only thing I could think might be an issue is being able to fire it out of battery, but if they designed it properly it shouldn’t be able to.

 

[FrancoisG3784]

Okay my friends, I scanned the manual (specifically pages describing disassembly and parts list, and diagrams).
View attachment 1152684

View attachment 1152685

View attachment 1152686

I wonder if the tactical version can use standard AR pistol grips in case we want to change it, also wonder if the buffer tube it commercial or mil-spec?

 

[machone]

I played around with this rifle again this morning, and I think the failure to feed is user error.

The mag release is right where my finger goes when it's not in the trigger guard. The mag release spring would have been plenty strong if it was a push button, but it's a long lever giving you pretty good mechanical advantage over the release. Just having your finger laying on the lever causes the magazine to not lock in correctly...not enough if the bolt is closed, too much if the bolt is open. If you keep your finger away, you can smack the magazine and it has positive lock and no failures to feed.

Version 2 needs a stronger mag release spring or it needs to be away from the index finger. It's very convenient, so the spring is probably the answer.

 

[Can-down]

I played around with this rifle again this morning, and I think the failure to feed is user error.

The mag release is right where my finger goes when it's not in the trigger guard. The mag release spring would have been plenty strong if it was a push button, but it's a long lever giving you pretty good mechanical advantage over the release. Just having your finger laying on the lever causes the magazine to not lock in correctly...not enough if the bolt is closed, too much if the bolt is open. If you keep your finger away, you can smack the magazine and it has positive lock and no failures to feed.

Version 2 needs a stronger mag release spring or it needs to be away from the index finger. It's very convenient, so the spring is probably the answer.

Thanks for the update, that sounds like a pretty easy fix!

 

[iHaVoc]

I played around with this rifle again this morning, and I think the failure to feed is user error.

The mag release is right where my finger goes when it's not in the trigger guard. The mag release spring would have been plenty strong if it was a push button, but it's a long lever giving you pretty good mechanical advantage over the release. Just having your finger laying on the lever causes the magazine to not lock in correctly...not enough if the bolt is closed, too much if the bolt is open. If you keep your finger away, you can smack the magazine and it has positive lock and no failures to feed.

Version 2 needs a stronger mag release spring or it needs to be away from the index finger. It's very convenient, so the spring is probably the answer.

Great follow-up, thank you! This had me pretty worried but knowing its possibly just a design flaw means it CAN be mitigated like you said. Mine comes in any day, and ill provide an update and video of what it looks like in action at the range!

 

[FrancoisG3784]

Thank you for the detailed report, much appreciated! The next best thing to original Glock mags are the Magpul Pmags for Glock pistols. They have a reputation of feeding just as reliably and cost a bit less.

As for the insertion issues, the Glock mags have a cutout into which the mag catch protrusion is supposed to "snap in". Hence why you can insert a Glock mag into a Glock pistol with the slide open and never have an issue. The mag makes an audible "click!" when it is fully seated. I would assume that the problem is there : the Derya needs to copy the Glock mag catch in order to be 100% reliable with the bolt open or closed.

With any luck, it is perhaps just a matter of proper fitting (filing or sanding) to make it work more smoothly. It is possible that the mag catch is just poorly cast and doesn't fit into the mag cutout very well. Perhaps the mags' cutouts are not made or positioned properly on the magazines themselves. Or perhaps the mag catch spring is too weak and doesn't engage strong enough...? Impossible to tell without taking the firearm apart and doing an in-depth inspection / function test.


I generally hate buying a project gun right out of the box, but this puppy sure looks like it's worth a bit of tinkering with!

Haven’t shot mine yet but yes the pump is stiff but that should become easier with use and it’s not that stiff, not any stiffer than my brand new Mossberg Maverick 88 12 gauge, just work it with authority, it uses a locking block which is why it’s stiff to pump back but it’s smooth on the forward stroke, the trigger is light and way better than I was expecting, good trigger, I don’t have snap caps to test the feeding which I probably should get if I want to test that, it’s light and handy, when I have the stock extended it’s easier to pump and I’m assuming because you have more leverage with your arm extended, you could put some grippy MLOK covers on the MLOK sized slots on the pump, the whole upper and lower receiver including the trigger guard/pack (kind of like on a shotgun), the buffer tube and adapter is all aluminum, the trigger I think is polymer but it’s nice. Yes you can over insert the magazine with the bolt open but you would have to ram that in hard to do it, it only happened to me if I held the mag release lever down, but without doing that with the bolt open the mag clicks in and audibly like you said so the other guy has to be shoving those mags in to jump past the mag catch, with the bolt open the mags insert easily and drop free but with the bolt closed it’s stiff to insert and they don’t drop free, I’m guessing with the bolt closed it probably puts pressure on the magazine enough to tilt it and makes rub on the mag well, the mags I tried are the 2 included mags which are a clone of the original Glock mags, I haven’t tried my pmags or my one OEM Glock brand mag, I can test how those ones insert and release and reply again to mention how they are going in and out, the other guy mentioned hand loads, I only shoot factory loaded ammo and will find out how it runs when I get the chance to shoot it, I think I’ll order snap caps in the mean time because I don’t know when I’ll be able to go out and shoot, it’s well made and I noticed they left the original notch rear sight on the rifle even though it has a full length rail and no front sight and was like why would they do that? But then noticed in the box they included the original front blade sight in case you want to take the front half of the rail off and use the original iron sights, the rear sight can be easily removed by taking the screw out and punching out the pin that attaches it to the rifle.

 

[KyleSchenk]

I wonder if the tactical version can use standard AR pistol grips in case we want to change it, also wonder if the buffer tube it commercial or mil-spec?

Grips without a beaver tail will work just fine. I confirmed yesterday. The buffer tube is proprietary. It uses a female threaded socket to engage the reciever adapter. As far as tube diameter, mine measures 1.156" in diameter. Some sticks may fit while some won't. Depends on how close to either tolerance the specific brand of stock is.

 

[FrancoisG3784]

Thank you for the detailed report, much appreciated! The next best thing to original Glock mags are the Magpul Pmags for Glock pistols. They have a reputation of feeding just as reliably and cost a bit less.

As for the insertion issues, the Glock mags have a cutout into which the mag catch protrusion is supposed to "snap in". Hence why you can insert a Glock mag into a Glock pistol with the slide open and never have an issue. The mag makes an audible "click!" when it is fully seated. I would assume that the problem is there : the Derya needs to copy the Glock mag catch in order to be 100% reliable with the bolt open or closed.

With any luck, it is perhaps just a matter of proper fitting (filing or sanding) to make it work more smoothly. It is possible that the mag catch is just poorly cast and doesn't fit into the mag cutout very well. Perhaps the mags' cutouts are not made or positioned properly on the magazines themselves. Or perhaps the mag catch spring is too weak and doesn't engage strong enough...? Impossible to tell without taking the firearm apart and doing an in-depth inspection / function test.


I generally hate buying a project gun right out of the box, but this puppy sure looks like it's worth a bit of tinkering with!

So I tested mag fitment like I mentioned I was going to in my previous reply to your comment, the clone Glock mags it comes with easily insert and drop free with the bolt open and are stiff to insert and pull out with the bolt closed, my OEM Glock mag is stiff to insert and pull out whether the bolt is opened or closed and doesn’t drop free either way, my MAGPUL Glock PMAG’s easily insert and drop free with the bolt opened or closed, I still need to get snap caps to test the feeding and ejection as I don’t know when I’ll get to time to shoot it, but so far the the PMAG’s are looking like the best option for the rifle.

 

[FrancoisG3784]

OK, took it to my outdoor range on Sunday and shot 100 rounds.

The good - reasonably accurate at 20 yards with a red dot I put on it. It does appear to be "not so stiff" after the 100 rounds but still you yank the slide back/forward. There is no spring assist either way.

The bad - so many FTF issues. I only tried the two included magazines and my 115gr (Campro bullet) handloads but the magazine can go in/out about 1/4 inch so if it's not inserted just right the round hits the feed ramp and does not chamber.

As someone else said, it works better if you insert the magazine with the slide forward. With the slide open, the magazine can be inserted too far.

I HAVE NOT TRIED ANY GLOCK BRAND MAGAZINES. I do not own a Glock. A friend will be loaning me some actual Glock magazines to try.

I will also try some factory ammo - maybe my handloads (which work fine in my pistols and previously in my PCCs) have the bullet in too far or out too far? Maybe I need 147gr bullets not 115gr?

The foregrip/slide is small and slippery. Gave myself a good blood blister when my ring finger got pinched between the slide and the action.

The gun is light-weight. I first put an LPVO on it, then a Bushnell 1.5-4.5x32 scope and both made the gun very top-heavy so red dot for me.

Added a loudener to the muzzle just because.

YMMV

Looks like the MAGPUL Glock PMAG’s are the best option, I haven’t tested feeding yet but they easily insert and drop free with the bolt opened or closed, the clone Glock mags it came with only easily insert and drop free with the bolt open and are stiff to insert and don’t drop free when the bolt is closed, my OEM Glock mag is stiff to insert and pull out whether the bolt is opened or closed, so my guess is the PMAGS are the way to go for this rifle if they feed properly as well, I need to buy snap caps to test the feeding and when I have the time to shoot I’ll see how that goes.

 

[762mm]

So I tested mag fitment like I mentioned I was going to in my previous reply to your comment, the clone Glock mags it comes with easily insert and drop free with the bolt open and are stiff to insert and pull out with the bolt closed, my OEM Glock mag is stiff to insert and pull out whether the bolt is opened or closed and doesn’t drop free either way, my MAGPUL Glock PMAG’s easily insert and drop free with the bolt opened or closed, I still need to get snap caps to test the feeding and ejection as I don’t know when I’ll get to time to shoot it, but so far the the PMAG’s are looking like the best option for the rifle.

I concur.

My original Glock-branded mags are having issues, but the 10/17 Magpul P-mags work great.

.

 

[Deathrawt]

The SGM 30 rounders or whatever they hold feed and function fine in my rifle but they do not drop free on their own which isn’t a big deal to me as long as they work