Modify a 303 Brit lee loader for 7.62x39?

mwells72774 · March 5, 2015, 10:54 AM

Looks possible but what would be necessary? Lee loaders are neck sizers so would all I need to do is trim the length of the die body to length?

kilimanjaro · March 5, 2015, 08:41 PM

You'll just end up with a ruined die set. Go spend $30 on the correct dies.

**Unclenick** · March 5, 2015, 10:14 PM

There are three problems. One is that the standard neck sizer needed for a standard 7.62×39 is 0.001" smaller than for a .303 British. It's because the standard bullet size in the SAAMI drawing is 0.0015" smaller in the Brit. So the 7.62×39 necks sized by the .303 die won't grip bullets as firmly.

The second problem is the shoulder angle on the 7.62×39 at 35° is steeper than the 33.93° angle on the Brit. It'll mean either about 0.016" less of the neck will be sized, which doesn't mean a lot, or that pounding the case into the die may push the outside edge of the shoulder back during sizing and that could allow the neck and shoulder junction to jam pretty hard into the chamber neck at the corner. There's a chance of that raising pressure.

The third problem is that there will be lateral wiggle room in the die for the narrower 7.6×39 case, and that will mead that it can size the neck slightly tilted off the rest of the case axis. That can affect accuracy adversely.

Unfortunately they don't make a Lee Loader for this chambering, so it means spending money. But I think if you eBay the loader you have and put the money toward a Lee Hand Press Kit and a set of their RGB dies, you'll have a tool you can do other calibers with as well as the one you want. It'll be faster, too. The only basic thing you'll be missing there is a means of measuring powder, but you were going to need that even if the Lee Loader cut down had worked out.

mwells72774 · March 5, 2015, 10:27 PM

I've got RCBS dies, just throwing wild thoughts out there. Ive got an old loader thats in rough shape so thought about it.

March 5, 2015, 10:54 AM	#1
mwells72774 Senior Member Join Date: May 3, 2011 Posts: 325	Modify a 303 Brit lee loader for 7.62x39? Looks possible but what would be necessary? Lee loaders are neck sizers so would all I need to do is trim the length of the die body to length?

March 5, 2015, 10:14 PM	#3
Unclenick Staff Join Date: March 4, 2005 Location: Ohio Posts: 21,063	There are three problems. One is that the standard neck sizer needed for a standard 7.62×39 is 0.001" smaller than for a .303 British. It's because the standard bullet size in the SAAMI drawing is 0.0015" smaller in the Brit. So the 7.62×39 necks sized by the .303 die won't grip bullets as firmly. The second problem is the shoulder angle on the 7.62×39 at 35° is steeper than the 33.93° angle on the Brit. It'll mean either about 0.016" less of the neck will be sized, which doesn't mean a lot, or that pounding the case into the die may push the outside edge of the shoulder back during sizing and that could allow the neck and shoulder junction to jam pretty hard into the chamber neck at the corner. There's a chance of that raising pressure. The third problem is that there will be lateral wiggle room in the die for the narrower 7.6×39 case, and that will mead that it can size the neck slightly tilted off the rest of the case axis. That can affect accuracy adversely. Unfortunately they don't make a Lee Loader for this chambering, so it means spending money. But I think if you eBay the loader you have and put the money toward a Lee Hand Press Kit and a set of their RGB dies, you'll have a tool you can do other calibers with as well as the one you want. It'll be faster, too. The only basic thing you'll be missing there is a means of measuring powder, but you were going to need that even if the Lee Loader cut down had worked out. __________________ Gunsite Orange Hat Family Member CMP Certified GSM Master Instructor NRA Certified Rifle Instructor NRA Benefactor Member and Golden Eagle

March 5, 2015, 08:41 PM	#2
kilimanjaro Senior Member Join Date: November 23, 2009 Posts: 3,963	You'll just end up with a ruined die set. Go spend $30 on the correct dies.

March 5, 2015, 10:27 PM	#4
mwells72774 Senior Member Join Date: May 3, 2011 Posts: 325	I've got RCBS dies, just throwing wild thoughts out there. Ive got an old loader thats in rough shape so thought about it.