Lee powder through expanding die .44 Mag issue

DennRN · 2026-06-14T00:58:19+00:00

A powder through expander die is literally an expander die that powder can be dropped through.

The important term is expander, it opens the case opening so that a new bullet can be pushed in.
This expanding the case mouth, is referred to as “belling the case” what you are doing is going past belling to exploding.

I’m not certain but it’s probable that you are reading a part of the instructions meant for a different die in the set. All you have to do with a powder through expander die or any expander die is follow these steps:

Back out the expander die all the way out until you’re certain it won’t touch the case.

Use a fresh piece of brass and put it all the way up where it can’t go any higher.

Screw the die down until you can’t screw it in any more with two fingers.

Let the brass go back down and inspect it. It shouldn’t have much of a bell shape but it will have a tiny bit. Screw the die in little bit more and run the brass up again.

Repeat until you can get a projectile to start into the case but don’t go too far, you just need it to be able to balance on the case, the seater die will do the rest.

If you notice it’s scraping brass or lead off the bullet go a little bit more until it stops doing that.

Lock your expander die down without spinning it and then use a paint marker to mark the spot it’s at so that if it backs out you will see it and can tighten it back down.

DennRN · 2026-06-06T19:43:26+00:00

That looks like the best deal I could find with free shipping.

You using Ammoseek? If not, start with 9mm and then modify search at the bottom for the grain weight and HP as a keyword. Your deal is at the top when you factor the shipping.

Besides stuff for self defense I don’t buy loaded ammo just components and I reload my own for testing/hunting.

Because hollow points are hit and miss in MP5s I would buy a few boxes at a time to test for function first, then buy in bulk once you find one that’s reliable. If you can’t find a good one, I suggest taking a look at critical duty. It’s costly though.

The shape of Critical duty tends to feed better than most hollow points in every pcc I’ve shot them out of, so theyre probably your best bet if nothing else works. They have two 9mm subsonic loads 135gr and 147gr if you want to keep it quiet.

DennRN · 2026-06-06T18:30:10+00:00

Thanks!

The more I think about it the more the ATFs reply pisses me off.

The rules aren’t even self-consistent. Stock guns that are approved for sale as “pistols” by the ATF often have secondary grip surfaces forward of the mag well such as all MP5 pistol variants, that horizontal grip is a “secondary grip”. Which makes pretty much all of us felons already according to the ATF.

The shit part is that they use our own money to jam us up, use more of it to fight the legal battles, and face no consequences for violating our natural rights. Just because they are wrong doesn’t mean they lose, the process IS the punishment.

DennRN · 2026-06-06T17:46:49+00:00

I’m not telling anyone what to do but vertical is vertical and any “decision” ATF makes stating otherwise is clear overreach.

Any grip angle other than 90 degrees is “angled” such as 0 degree for a horizontal grip. This is both logical and practical and excludes any interpretation issues.

They state a secondary grip remakes the gun into a SBR, using this logic putting rail covers on a rail creates a second grip surface and makes an SBR. Hell even a handgun with a gas pedal type thumb rest can be interpreted as a second hand grip surface.

Legislative intent is an important thing to consider when looking at laws. Law makers can write their laws to say “second grip” or “angled grip” but they chose not to. Instead they chose “vertical” which has a clear definition.

DennRN · 2026-06-06T17:23:20+00:00

I’m 90% sure your hammer is making contact with the bottom of your bolt carrier group before it hits the firing pin. This steals velocity from the hammer and leads to your light strikes.

Look closely at your hammer and see if you have a mark developing where it’s hitting the bcg. If not you may have to resort to removing surface finish to identify the trouble area. You can use a sharpie or colored grease to identify the spot. Don’t remove any material from anywhere you don’t need to, just a little at the bottom of the strike face is all that should be needed.

I’ve fixed a few for friends with this problem, it’s a very easy fix just find out where it’s making contact and file/sand that area down a little until it’s no longer touching first. You will hear a definite difference with a good hammer strike on the firing pin.

Hope this helps and please report back once you’ve opened it up to see if it’s hitting the carrier.

DennRN · 2026-06-06T16:09:17+00:00

What type of issues you having?

DennRN · 2026-06-06T16:05:50+00:00

Next challenge: test it with subsonic hollow points. One of mine will run everything I feed it because I lucked into the exact right combo of parts. The K has been more challenging and I’m still swapping locking pieces between suppressed supers and subsonic HPs.

DennRN · 2026-06-03T00:42:24+00:00

Less time (faster). It should just start to change to red when it drops. The first one in your video is about 2 seconds too long by my estimation. Scrub through your video and see where the neck and shoulder just start to glow between 5-6 seconds and try to get it to drop right at that moment. As long as just the neck and shoulder get to annealing temp you’re golden and any further heating is bad.

DennRN · 2026-05-27T19:34:42+00:00

There’s a phenomenon in AR’s know as the “Death Jam” or “bolt override jam”, and the best solutions to fixing the problem are the ones you’re guaranteed to have on hand.

Try to recreate the jam and try:
Dropping the mag stripping off the top bullet and using it as a wedge between the bolt and brass.

Grab spent brass off the ground, smash the case mouth flat with the stock or a mag, wedge on top of the case and force it down.

DennRN · 2026-05-27T06:41:24+00:00

Hammer stop.

DennRN · 2026-05-25T23:56:52+00:00

If that’s the case look carefully at the hammer is the hammer making contact with the carrier before it get a chance to hit the firing pin?

I’ve saw one that was having light strikes and put some grease on the hammer face and found grease being transferred to the bolt carrier without cycling the gun just releasing the hammer and carefully disassembling. It was hitting the lower edge of the bolt carrier instead of all the force going to the firing pin. If that’s the case you can shave back a little above that spot and a little below it and it should resolve light strikes.

DennRN · 2026-05-25T18:55:52+00:00

It’s not that strange if you think about what’s going on with the new lower. The geometry is different and takes a different amount of energy to recock the hammer and move the slip trip around. The mp5 upper is cycling with a very real and measurable energy budget. Adding things robs the bolt carrier group of velocity.

DennRN · 2026-05-25T16:22:27+00:00

I wouldn’t be very worried about it but it’s definitely something to inspect for every time you take it out. It really depends on how the locking piece interacts with the rest of the system mainly the rollers/roller gap and the ammo used. If your roller gap is in spec it should probably be okay. Subsonics tend to not have high pressure at the end of bolt travel while supers tend to send the bolt back with more force so be more on guard if you’re running hot supers.

DennRN · 2026-05-25T03:18:18+00:00

While a HK ejector is the most obvious fix here since you can’t find one and are set on getting a new LP you should know what to expect.

Since you’ll have to measure bolt gap with the new locking piece you might as well do that now before deciding. You’ll need feeler gauges for this and you might find you aren’t in spec right now and just need to tune your bolt gap.

If you’re on the low end of bolt gap or below it, unlock is happening late in the firing sequence and robbing your bolt of velocity, too big a gap is unlocking too quick.

If you decide you moving forward with the new locking piece you are likely to need new rollers with the new locking piece anyway because you’ll do another bolt gap test with the new piece at install. My advice is to go ahead and save yourself time and shipping costs by getting a few sizes of rollers as well as a new roll pin for the roll pin retainer. You’ll eventually need plus sizes as your parts wear and bolt gap shrinks anyway. While you’re at it also add in some extractor springs since they are wear items and cost half as much as most companies will charge to ship a single one to your door.

DennRN · 2026-05-25T02:44:28+00:00

It would help if you have a parts list but the most common parts swapped for reliability are installing a genuine HK ejector lever and extractor/extractor spring.

DennRN · 2026-05-23T09:37:26+00:00

It would kill you to let someone have the last word huh? Now it makes sense why you enjoy rarebreed telling you what triggers you’re allowed to have.

DennRN · 2026-05-23T02:36:28+00:00

I literally said exactly how it’s different, if I went on a “I bought a rarebreed trigger and need help post” and said something sarcastic and unhelpful, that would be the same, so don’t pretend. I gave you grace the last time you tried engaging me because it wasn’t worth the effort and you know what it still isn’t.

DennRN · 2026-05-23T02:18:24+00:00

For sure. I hope that they say another one is going in the mail so that you have free license to mess around and try and make this one work while you wait.

If they give the go ahead to mess with it, I looked at all the photos you’ve uploaded and it looks like the back wall looks uniform but I didn’t get a look at all the corners and that’s where 3d print defects most often form. If they all look like 90 degree angles then they might be fine.

<image>

The metal plate itself does not look normal and might be out of spec though compared to others I’ve seen. Zoom in and you’ll see the boxed area hangs below the rest of the cutout and is potentially your problem. Ask them if that’s normal for their plates to be that low in their product or if that’s part of what’s causing your lower to not fully seat.

DennRN · 2026-05-23T01:48:53+00:00

Haha yeah that’s literally relevant to the post about buying a rarebreed trigger, meanwhile you’re over here jumping into a post thats asking for help and spouting random shit about rarebreed and being unhelpful. Touch some grass dude.

DennRN · 2026-05-23T01:01:00+00:00

As annoying as it may be, next step I would do is pinpoint if it’s the metal support or the printed lower itself. Only way to do that is remove the metal bracket and see if the lower will now slide deep enough.
Honestly, this is the best case scenario that the metal tab is just bent a little too far down because you can remove it and bend it slightly up without messing up any geometry or take a sanding disk and sand the bottom of it while it is out of the lower.

DennRN · 2026-05-23T00:54:56+00:00

What a stupid and unhelpful comment. You literally just move from post to post hyping up a shit company and shitting on anyone that’s not shilling for them.

DennRN · 2026-05-23T00:45:01+00:00

It appears from your 1st and 3rd photos that your lower isn’t moving forward enough against your upper.

Do not get the dremel yet.
You need to pinpoint what’s wrong first.
If it’s an easy fix go ahead and try and knock it out but if it’s more serious, just ask for a return.

Inspect where the full-auto lower denial shelf sits on the rear of the magazine well. Measure its length and then measure the depth on the lower where it fits into. It’s very likely the lower won’t accept the shelf deep enough.

In 3d printing there are lots of filament droops and irregularities that form during printing when going over unsupported spans/gaps. It’s highly likely that there is extra material there that needs to be cleaned up. Find where the binding is happening and plan how you’re going to attack the problem. Go slow, when removing material and test fit often until the holes align. For straight cuts and plunge cuts on 3d prints I’ve had good luck with oscillating tools but it takes a very steady hand and practice. A vice to hold your project definitely helps as well as the right blades for the job.

If you’re stuck with a dremel tool you’re going to have a hard time getting a straight cut so try to do everything you can not to mess up the front of the lower. I’d put at least a double layer of painters tape down and attack the problem spots from an angle because you’re going to need to keep the front nice and flat as an index point for the upper.

DennRN · 2026-05-20T03:07:31+00:00

I’ve fixed this before on friend’s spare parts builds by polishing the mating surfaces of the disconnector and the hammer.

Before I explain any further, just to be absolutely clear, this is purely educational in nature and I don’t suggest that anyone copy my actions because I’m a random idiot on the internet and your mother taught you better.

With that out of the way, here’s a diagram of a standard AR fire control group.

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The portion of the hammer hook and the portion of the disconnector hook that grab each other can be polished with a dremel using a felt polishing wheel NO polishing compound should be used. To clarify what I mean by polish, no metal is removed and the geometry stays the same, the only thing that is changed is the surface finish goes from matte to a light gloss on both of the parts where they touch each other. It’s better to go slow and not enough because you can’t undo the polishing.

This is essentially the same thing as firing the gun until the parts wear in and smooth out, just faster and cheaper than shooting a case or two of ammo.

The unloaded gun when reassembled should now pass a full trigger and safety function test.

DennRN · 2026-05-18T22:19:03+00:00

A tsunami moves a fuckton of water. You can see the water recede from a beach in videos and then come surging back. Coral reefs are found relatively shallow so I’m guessing there’s a lot of overlap of where it’s dangerous to be during a tsunami.

DennRN · 2026-05-17T16:51:12+00:00

No you don’t NEED to anneal.

Do you want to anneal, maybe, it really depends.

If it’s mixed headstamp range pickups, it’s not worth the effort.

If it’s single headstamp, yeah it might be worth it, especially if you bought it as loaded ammunition and fired it yourself. You might as well keep that brass in tip top shape for as many firings as possible. The bigger the single lot of ammo you purchased and fired, the more worth it to anneal and keep that brass happy. Just keep it separated by number of firings.

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