Expander Mandrels

[Sheldon N]

So I've been using an expander mandrel for a few years now and I'm running into an odd issue. I've been using the expander for .223, .308, and 6.5 Creedmoor and only see this issue on 6.5 Creedmoor.

Check your brass for donuts inside the case neck at the junction where the neck meets the shoulder. Possible that repeated sizing has caused a ring of brass to form inside the case which is putting up significant resistance for the mandrel and causing the case to collapse. The way to check for this would be to take a fired, unsized case and see if you can press or drop a bullet into the case without any resistance. If it drops in freely then I doubt donuts are the issue, if it hits a hard stop partway in then you've probably got donuts.

For an expander mandrel I would prefer to open the case up closer to 1 or 2 thousandths from FL sizing, but 0.004 isn't out of the question. You can adjust this with either bushing size or having a die custom honed to the desired neck diameter.

I suspect you are using an "expander" mandrel rather than a "turning" mandrel. They are 0.001 thou different in size, with the expander mandrel being the larger of the two and typically 0.001 under bullet diameter. The turning mandrel is 0.002 under bullet diameter. I use the "turning" mandrels as I prefer 0.002 of neck tension. Switching to a turning mandrel will reduce the sizing force needed.

Upgrading to a better mandrel material will also noticeable reduce the amount of friction/effort for sizing with the mandrel. Look at either the Sinclair Carbide, 21st Century TiN coated, or the 21st Century Black Nitride turning mandrels.

 

[Billiam1211]

Check your brass for donuts inside the case neck at the junction where the neck meets the shoulder. Possible that repeated sizing has caused a ring of brass to form inside the case which is putting up significant resistance for the mandrel and causing the case to collapse. The way to check for this would be to take a fired, unsized case and see if you can press or drop a bullet into the case without any resistance. If it drops in freely then I doubt donuts are the issue, if it hits a hard stop partway in then you've probably got donuts.

For an expander mandrel I would prefer to open the case up closer to 1 or 2 thousandths from FL sizing, but 0.004 isn't out of the question. You can adjust this with either bushing size or having a die custom honed to the desired neck diameter.

I suspect you are using an "expander" mandrel rather than a "turning" mandrel. They are 0.001 thou different in size, with the expander mandrel being the larger of the two and typically 0.001 under bullet diameter. The turning mandrel is 0.002 under bullet diameter. I use the "turning" mandrels as I prefer 0.002 of neck tension. Switching to a turning mandrel will reduce the sizing force needed.

Upgrading to a better mandrel material will also noticeable reduce the amount of friction/effort for sizing with the mandrel. Look at either the Sinclair Carbide, 21st Century TiN coated, or the 21st Century Black Nitride turning mandrels.

Ok - I think this is pointing me in the right direction. I went ahead and ordered a new mandrel from 21st Century with a smaller sized mandrel option. If this doesn't work it looks like I'll have 2 options: either get new brass or start trimming the donut. At the moment, I'm reloading Peterson Brass that has 3 firings. After giving the bullet drop test a shot, it did go in all the way but I certainly noticed resistance as it entered the neck/shoulder junction so I'm thinking the donut may be a factor. Thanks for the response!

 

[Billiam1211]

Lunch break update. So I tumbled my brass for a few hours while I was working with polish in the media. I FL sized 25-30 pieces brass and then expanded the necks. No lube inside the necks and the ram stroke was smooth as butter.

Welp, I'm a moron... the inside of the case necks were just dirty and my reloading process got lazy. I've been tumbling brass after sizing to remove the lube, but guess I need to tumble before and after now

 

[Darkhorse1]

So I've been using an expander mandrel for a few years now and I'm running into an odd issue. I've been using the expander for .223, .308, and 6.5 Creedmoor and only see this issue on 6.5 Creedmoor.

I'm using Peterson brass, Whidden dies, and the Sinclair expander with carbide mandrel. After FL sizing using Redding's imperial case wax, I use a q-tip and get some lube inside the case necks prior to running them in the expander. When the expander is clean, it works fine, but after expanding a few necks it starts to bind up. If I don't clean the expander after every 2 or 3 cases- I run the risk of destroying the case on the down stroke. If I don't apply lube, I'll definitely destroy the case on the downstroke. The odd thing is this doesn't happen on .223 or .308 and they go through the expander with ease and probably don't even need lube. I measured the mandrel with my calipers and it's showing 0.264 inches so is it possible I got an out of spec mandrel? Any ideas what I'm doing wrong with the 6.5 Creedmoor then?

View attachment 7739148

Only time this happened with me was when I was using the same mandrel on two different cartridges (both .264 bullets though), forgot to reset the die in the press for 6.5 sst, and it did the exact thing your pic shows due to the mandrel bottoming out. Doesn't sound like that's quite what is happening in your case however. So for ex if you set the die for 223, and didn't back it off for when you swap to 6.5, that would happen (also would happen on the 308 though so don't think this is it, just figured I'd share).

 

[XikoPlavi]

Without reading every reply in this lonnnggg thread. I’d have to say that this is the most misunderstood part of precision loading. Redding has revamped thier written answer to this question. Go look it up. I dont think anyone truly knows what is best. Just get good results is all that matters it seems. Buy 3 different sized bushings and play around with it for different chambers. Some buy the bushing dies and don’t use the bushing. Some do use It and the mandrel. I bought the mandrel and use it every time, but I also use the bushing and FL resize every time. I have seen some people say they never FL resize and only neck size. It’s a joke honestly ( it just confuses everyone). I’ve seen some say they never aneal. Then most say to aneal every time. I dont think anyone really knows for sure.

 

[CK1.0]

Without reading every reply in this lonnnggg thread. I’d have to say that this is the most misunderstood part of precision loading. Redding has revamped thier written answer to this question. Go look it up. I dont think anyone truly knows what is best. Just get good results is all that matters it seems. Buy 3 different sized bushings and play around with it for different chambers. Some buy the bushing dies and don’t use the bushing. Some do use It and the mandrel. I bought the mandrel and use it every time, but I also use the bushing and FL resize every time. I have seen some people say they never FL resize and only neck size. It’s a joke honestly ( it just confuses everyone). I’ve seen some say they never aneal. Then most say to aneal every time. I dont think anyone really knows for sure.

 

[XikoPlavi]

View attachment 7744061

Otay butwheat , I can live with your meme. I suppose I didn’t make any sense there after iI reread, but whatever. I just think this whole subject gets confusing to alot of reloaders and felt like replying even though I knew I should not have replied LOL

 

[30cal user]

Double check the mandrel and bushings once you get them in hand with your calipers