7.62x39 expander size?

Shadow9mm · March 5, 2023, 11:14 AM

Quick question,
For 7.62x39, will using a .311 expander be ok with .310 bullets? I do plan to crimp the bullets to make sure they don't get set back.

Explanation,
I bought the lee Pace setter die as it was inexpensive and I don't plan to load a lot of 7.62x39. As I understand it, it comes with 2 expanders, a .308 and a .311. The bullets I have are .310, 123g Hornady SST marked specifically for 7.62x39. My thought was that, with a .310 bullet and a .311 expander, it should have enough neck tension to hold the bullet, and using a firm crimp it should be adequate to run in my AK.

Side Notes,
I did not plan to load for 7.62x39. I looked into it a fair bit when I got my AK but it was far to expensive IMHO compared to buying steel cased ammo. However I wanted some good hunting/defensive ammo and It has been unobtainable for me due to price or availability since I got the gun. Well, I walked into the shop yesterday and they had the Hornady 123g SST for $18.99 per 100 and I ended up buying 500 along with some powder, brass, and dies, already have primers. I don't know that I plan on loading anything beyond these 500. But only time will tell.

lugerstew · March 5, 2023, 12:35 PM

If you want, I have an RCBS die set for 7.62x39, I could measure the expander ball, also, I would say try pressing a bullet in, if there is not enough neck tension, then put the decap rod and ball in a drill and sand off a thousandth at a time until you have what you want for neck tension.

Shadow9mm · March 5, 2023, 02:25 PM

Quote:

Originally Posted by lugerstew

If you want, I have an RCBS die set for 7.62x39, I could measure the expander ball, also, I would say try pressing a bullet in, if there is not enough neck tension, then put the decap rod and ball in a drill and sand off a thousandth at a time until you have what you want for neck tension.

That would be great. thank you.

The dies will be here later today. Once they come in I will dig out my micrometer and start getting some measurements and go from there. I'm hoping I don't have to do any sanding, but we will see.

HiBC · March 5, 2023, 03:04 PM

Maybe size a piece (or two ) of fired brass. Use the expander in question.
Measure the OD of the neck . Record . Seat a bullet . Measure again.

The change would be your neck tension. I don't know what is ideal. I guess .002 or .003.

You said you have an expander button for .308 and .311 bullets. Its good to have a spare decap/expander spindle on hand. I've had an off center flash hole cause a wreck that bent a spindle.
Thats frustrating when the plan is going shooting. Having a spare spindle puts you back in production.

It also gives you a spare expander button so you can boldly polish the button to the diameter you need.

lugerstew · March 5, 2023, 03:22 PM

In my RCBS die set, the .308 expander ball measures about .305, the .311 expander ball measures about .308.
I have been loading those exact same bullets with the .311 expander ball and they seem to have plenty of neck tension and I have shot hundreds of rounds in my AK47.

hammie · March 5, 2023, 03:27 PM

@Shadow: I have your exact same dilemma. I recently purchased a 7.62x39mm bolt rifle. My RCBS dies came with two expanders: one for .308 and one for .311 diameter bullets. Because of the elliptical shape of the expander balls, it was difficult to get a good measurement, but they seemed to measure about .002 to .003 inch below the corresponding bullet diameter. I also have a tungsten carbide neck expander, which measures .306 inch.

I'm using your same bullet: the 123 grain, .310 diameter Hornady's. I intend to try the carbide expander first, while making sure that there is an appreciable inside neck chamfer on the case. Hope it works. I prefer carbide expanders because there is much less effort on the press upstroke, and no squawking, and no lubing/cleaning the inside of the neck.

In your case, if the smaller expander doesn't work, you can always use the larger expander and apply a significant crimp. I imagine that you will be crimping anyway, for the auto-loading AK-47. Plus there is always HiBC's idea of polishing the larger expander ball down.

Edit: I just read lugerstew's response. Perhaps there's the answer. It seems the nominal .311 expander will work for .310 bullets.

tangolima · March 5, 2023, 03:32 PM

The .311 expander should work. It's for bullets larger than .308", 0.310" to 0.312". Such setup is a bit hard on the brass neck. It first sizes the neck down below what is needed for 0.308" bullet, and then expands it back for 0.312". Neck lube may be a good idea. Not everyone cares about 7.62x39 brass. You do if you handload it.

-TL

Sent from my SM-N960U using Tapatalk

Shadow9mm · March 5, 2023, 06:00 PM

Quote:

Originally Posted by tangolima

The .311 expander should work. It's for bullets larger than .308", 0.310" to 0.312". Such setup is a bit hard on the brass neck. It first sizes the neck down below what is needed for 0.308" bullet, and then expands it back for 0.312". Neck lube may be a good idea. Not everyone cares about 7.62x39 brass. You do if you handload it.

-TL

Sent from my SM-N960U using Tapatalk

That makes a lot of sense, hadn't thought about that aspect of it. Since its intended to use either diameter it will wind up over working the neck in time.

tangolima · March 5, 2023, 06:32 PM

It is not much really. I turned the neck wall a little thinner to make myself feel better. Annealing every 5 firings helps too. I have a batch of Lapua brass that has lasted forever. The over gassing SKS tears up the rims pretty bad though. I have an idea to improve that but haven't had a chance to try yet.

-TL

Sent from my SM-N960U using Tapatalk

Shadow9mm · March 5, 2023, 07:29 PM

so, just got the dies. dug out my micrometer measured the expander balls, one is .307, the other is .310. Gonna clean and lube the dies and do a little sizing.

tangolima · March 5, 2023, 08:01 PM

A bit of side note. Bullet setback in rifle usually doesn't cause increased MV (pressure). I tried that myself and it has been true for calibers with large rifle primer, and mixed with small rifle primer. Primer ignition pushes the bullet to contact rifling regardless seating depth. Small primer may not has energy to do that consistently.

-TL

Sent from my SM-N960U using Tapatalk

Shadow9mm · March 5, 2023, 08:30 PM

Ok, so got everything mostly up and running. Bullets cannot be pushed in or pulled out by hand using the .310 (for .311) expander ball. I will be adding a crimp into the cannelure as well so I should be good to go.

Unfortunately there is an issue with the bullet seater. I have the seating die adjusted down as far as it will go, and the seating stem screwed in as far as it will go and I cannot get the cannelure to the case mouth its off by about 0.080. With the lee dies the seating stem slides up into the adjustment knob. I put a .177 bb between the seating stem and the adjustment, it still left me 0.001 short of the listed COL. Will need to make some kind of spacer to put up in the thing.

tangolima · March 5, 2023, 08:45 PM

Quote:

Originally Posted by Shadow9mm

Ok, so got everything mostly up and running. Bullets cannot be pushed in or pulled out by hand using the .310 (for .311) expander ball. I will be adding a crimp into the cannelure as well so I should be good to go.

Unfortunately there is an issue with the bullet seater. I have the seating die adjusted down as far as it will go, and the seating stem screwed in as far as it will go and I cannot get the cannelure to the case mouth its off by about 0.080. With the lee dies the seating stem slides up into the adjustment knob. For now I put a .177 BB under the seating stem to make it push down a bit farther. but I doubt this will be a viable long term solution.

Don't worry. I do that all the time. Small screw nut, washers, even rolled up paper etc, I have used winky dings of all sorts. BB and bearing balls sounds good idea.

-TL

Sent from my SM-N960U using Tapatalk

Shadow9mm · March 5, 2023, 08:46 PM

Quote:

Originally Posted by tangolima

Don't worry. I do that all the time. Small screw nut, washers, even rolled up paper etc, I have used winky dings of all sorts. BB and bearing balls sounds good idea.

-TL

Sent from my SM-N960U using Tapatalk

I may try a couple small nuts, thats a fantastic idea! beats mine of filling it half full of JB Weld.

**Unclenick** · March 6, 2023, 11:01 AM

Quote:

Originally Posted by Tangolima

Bullet setback in rifle usually doesn't cause increased MV (pressure)

It can, though. It depends on the powder, case fill, bullet size, and all that. You can see some data and a plot of it for 30-06 with a round nose bullet on pages 46, 47, and 48 here.

Shadow9mm · March 6, 2023, 05:59 PM

Quick update, Kinda cool. I contacted Lee about the seating depth issue. They shipped me a new seating stem the next day. They sent me a "S PLG 7MMBR/6.5GREND" SKU SB3624. As best I can tell its a plug for 7mm BR and or 6.5 Grendel. They said it will allow me to seat the bullet deeper with my 7.62x39mm dies. Will update when I get it.

Mannlicher · March 7, 2023, 10:43 AM

I have loaded for the 7.62x39 commie round for several years now. I have been using those 123 grain .310 Hornady bullets as well. IMR 4198 and CFE BLK for powders. Accuracy is good, and they are hammers on medium size hogs and whitetail deer.
I adjust the expander of my RCBS die to accommodate the Hornady bullet.

RoyceP · March 7, 2023, 11:20 AM

Quote:

Originally Posted by Shadow9mm

Quick update, Kinda cool. I contacted Lee about the seating depth issue. They shipped me a new seating stem the next day. They sent me a "S PLG 7MMBR/6.5GREND" SKU SB3624. As best I can tell its a plug for 7mm BR and or 6.5 Grendel. They said it will allow me to seat the bullet deeper with my 7.62x39mm dies. Will update when I get it.

Lee's customer service has always been exceptional the few times I have dealt with them. Once I lost part of a press while taking it apart for a caliber change. Called them and they shipped the part to me at no charge.

Shadow9mm · March 11, 2023, 01:38 PM

Ok, so I received my new seating stem yesterday from lee. it got the job done. On a side note, the neck tension is definitely a little loose. There was enough powder in the seating stem, while threading it down, to push the bullet past the cannelure and all the way inside the empty case. oops

Shadow9mm · April 1, 2023, 12:41 PM

Update!

The new bullet seater works like a charm.

the .311 expander is definitely too large. As stated last time I pushed a bullet all the way into the case on accident when trying to screw the seating stem down to touch the bullet. I was also able to push the bullet back out today using a small allen wrench inserted through the flash hole.

I switched over to the .308 expander. seating pressure now feels normal and I am unable to push the bullet in with hand pressure.

Going to load up some test loads today.

March 5, 2023, 11:14 AM	#1
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	7.62x39 expander size? Quick question, For 7.62x39, will using a .311 expander be ok with .310 bullets? I do plan to crimp the bullets to make sure they don't get set back. Explanation, I bought the lee Pace setter die as it was inexpensive and I don't plan to load a lot of 7.62x39. As I understand it, it comes with 2 expanders, a .308 and a .311. The bullets I have are .310, 123g Hornady SST marked specifically for 7.62x39. My thought was that, with a .310 bullet and a .311 expander, it should have enough neck tension to hold the bullet, and using a firm crimp it should be adequate to run in my AK. Side Notes, I did not plan to load for 7.62x39. I looked into it a fair bit when I got my AK but it was far to expensive IMHO compared to buying steel cased ammo. However I wanted some good hunting/defensive ammo and It has been unobtainable for me due to price or availability since I got the gun. Well, I walked into the shop yesterday and they had the Hornady 123g SST for $18.99 per 100 and I ended up buying 500 along with some powder, brass, and dies, already have primers. I don't know that I plan on loading anything beyond these 500. But only time will tell. __________________ I don't believe in "range fodder" that is why I reload.

March 5, 2023, 03:27 PM	#6
hammie Senior Member Join Date: March 18, 2009 Location: Temple, TX Posts: 964	@Shadow: I have your exact same dilemma. I recently purchased a 7.62x39mm bolt rifle. My RCBS dies came with two expanders: one for .308 and one for .311 diameter bullets. Because of the elliptical shape of the expander balls, it was difficult to get a good measurement, but they seemed to measure about .002 to .003 inch below the corresponding bullet diameter. I also have a tungsten carbide neck expander, which measures .306 inch. I'm using your same bullet: the 123 grain, .310 diameter Hornady's. I intend to try the carbide expander first, while making sure that there is an appreciable inside neck chamfer on the case. Hope it works. I prefer carbide expanders because there is much less effort on the press upstroke, and no squawking, and no lubing/cleaning the inside of the neck. In your case, if the smaller expander doesn't work, you can always use the larger expander and apply a significant crimp. I imagine that you will be crimping anyway, for the auto-loading AK-47. Plus there is always HiBC's idea of polishing the larger expander ball down. Edit: I just read lugerstew's response. Perhaps there's the answer. It seems the nominal .311 expander will work for .310 bullets. Last edited by hammie; March 5, 2023 at 03:32 PM.

March 5, 2023, 07:29 PM	#10
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	so, just got the dies. dug out my micrometer measured the expander balls, one is .307, the other is .310. Gonna clean and lube the dies and do a little sizing. __________________ I don't believe in "range fodder" that is why I reload.

March 5, 2023, 08:30 PM	#12
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	Ok, so got everything mostly up and running. Bullets cannot be pushed in or pulled out by hand using the .310 (for .311) expander ball. I will be adding a crimp into the cannelure as well so I should be good to go. Unfortunately there is an issue with the bullet seater. I have the seating die adjusted down as far as it will go, and the seating stem screwed in as far as it will go and I cannot get the cannelure to the case mouth its off by about 0.080. With the lee dies the seating stem slides up into the adjustment knob. I put a .177 bb between the seating stem and the adjustment, it still left me 0.001 short of the listed COL. Will need to make some kind of spacer to put up in the thing. __________________ I don't believe in "range fodder" that is why I reload. Last edited by Shadow9mm; March 5, 2023 at 08:45 PM.

March 6, 2023, 05:59 PM	#16
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	Quick update, Kinda cool. I contacted Lee about the seating depth issue. They shipped me a new seating stem the next day. They sent me a "S PLG 7MMBR/6.5GREND" SKU SB3624. As best I can tell its a plug for 7mm BR and or 6.5 Grendel. They said it will allow me to seat the bullet deeper with my 7.62x39mm dies. Will update when I get it. __________________ I don't believe in "range fodder" that is why I reload.

March 5, 2023, 12:35 PM	#2
lugerstew Senior Member Join Date: September 22, 2019 Location: Colorado Posts: 261	If you want, I have an RCBS die set for 7.62x39, I could measure the expander ball, also, I would say try pressing a bullet in, if there is not enough neck tension, then put the decap rod and ball in a drill and sand off a thousandth at a time until you have what you want for neck tension.

March 5, 2023, 03:04 PM	#4
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,295	Maybe size a piece (or two ) of fired brass. Use the expander in question. Measure the OD of the neck . Record . Seat a bullet . Measure again. The change would be your neck tension. I don't know what is ideal. I guess .002 or .003. You said you have an expander button for .308 and .311 bullets. Its good to have a spare decap/expander spindle on hand. I've had an off center flash hole cause a wreck that bent a spindle. Thats frustrating when the plan is going shooting. Having a spare spindle puts you back in production. It also gives you a spare expander button so you can boldly polish the button to the diameter you need.

March 5, 2023, 03:22 PM	#5
lugerstew Senior Member Join Date: September 22, 2019 Location: Colorado Posts: 261	In my RCBS die set, the .308 expander ball measures about .305, the .311 expander ball measures about .308. I have been loading those exact same bullets with the .311 expander ball and they seem to have plenty of neck tension and I have shot hundreds of rounds in my AK47.

March 5, 2023, 03:32 PM	#7
tangolima Senior Member Join Date: September 28, 2013 Posts: 3,872	The .311 expander should work. It's for bullets larger than .308", 0.310" to 0.312". Such setup is a bit hard on the brass neck. It first sizes the neck down below what is needed for 0.308" bullet, and then expands it back for 0.312". Neck lube may be a good idea. Not everyone cares about 7.62x39 brass. You do if you handload it. -TL Sent from my SM-N960U using Tapatalk

March 5, 2023, 06:32 PM	#9
tangolima Senior Member Join Date: September 28, 2013 Posts: 3,872	It is not much really. I turned the neck wall a little thinner to make myself feel better. Annealing every 5 firings helps too. I have a batch of Lapua brass that has lasted forever. The over gassing SKS tears up the rims pretty bad though. I have an idea to improve that but haven't had a chance to try yet. -TL Sent from my SM-N960U using Tapatalk

March 5, 2023, 08:01 PM	#11
tangolima Senior Member Join Date: September 28, 2013 Posts: 3,872	A bit of side note. Bullet setback in rifle usually doesn't cause increased MV (pressure). I tried that myself and it has been true for calibers with large rifle primer, and mixed with small rifle primer. Primer ignition pushes the bullet to contact rifling regardless seating depth. Small primer may not has energy to do that consistently. -TL Sent from my SM-N960U using Tapatalk

March 7, 2023, 10:43 AM	#17
Mannlicher Senior Member Join Date: July 8, 2001 Location: North Central Florida & Miami Posts: 3,210	I have loaded for the 7.62x39 commie round for several years now. I have been using those 123 grain .310 Hornady bullets as well. IMR 4198 and CFE BLK for powders. Accuracy is good, and they are hammers on medium size hogs and whitetail deer. I adjust the expander of my RCBS die to accommodate the Hornady bullet. __________________ Nemo Me Impune Lacesset "The trouble with our liberal friends is not that they're ignorant; it's just that they know so much that isn't so.".........Ronald Reagan

March 11, 2023, 01:38 PM	#19
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	Ok, so I received my new seating stem yesterday from lee. it got the job done. On a side note, the neck tension is definitely a little loose. There was enough powder in the seating stem, while threading it down, to push the bullet past the cannelure and all the way inside the empty case. oops __________________ I don't believe in "range fodder" that is why I reload. Last edited by Shadow9mm; March 11, 2023 at 01:47 PM.

April 1, 2023, 12:41 PM	#20
Shadow9mm Senior Member Join Date: March 21, 2012 Location: Indianapolis, IN Posts: 3,990	Update! The new bullet seater works like a charm. the .311 expander is definitely too large. As stated last time I pushed a bullet all the way into the case on accident when trying to screw the seating stem down to touch the bullet. I was also able to push the bullet back out today using a small allen wrench inserted through the flash hole. I switched over to the .308 expander. seating pressure now feels normal and I am unable to push the bullet in with hand pressure. Going to load up some test loads today. __________________ I don't believe in "range fodder" that is why I reload.