thorn
03-23-2008, 07:01 PM
I've installed a factory PTX insert into my LNL-AP, and thought I'd pass along some casual initial impressions so that others can decide if it is an accessory worth purchasing.
The benefit of having a PTX (powder-through expander) is that it allows you to flare the case mouth in the same station as the powder measure, which can free up another station for a different purpose. In my case, I wanted to use a "powder cop" die in Station 3. Because I seat the bullet in Station 4 and taper crimp in Station 5, the only way to use a powder cop die was to free up Station 3.
INSTALLATION
The part itself is simply a tube with a tapered end, which replaces the powder funnel insert inside the powder drop tube. Replacing the part itself is easy, but unfortunately you may find there's more work needed when it comes to the powder measure.
The (bare-bone) instructions dictate that the powder measure assembly should be screwed into the die until it nearly touches the shell plate. Reattach the arm link and go on about your evening. Presumably, this will cause a full throw of the powder rotor as well as flare the mouth of the shell. However, in my case this didn't happen.
I spent about an hour having to adjust the linkage to the rotor, doing many tests with a shell casing to get the rotor to correctly perform a full up/down rotation. It was absolutely not a "drop-in part", requiring a lot of small tweaks, testing, retweaking, and retesting. Differences of 1/8" - 1/4" were very significant... it took quite a long time to find the optimal position for the link height.
MINIMAL EXPANSION
Once it was finally installed completely, I ran a few shells through and noticed the problem that others with PTX experience have reported. The PTX does not flare the case mouth very much at all... in fact, it is barely enough to do the job. I'm using 124gr FMJ bullets that measure .355" wide, and they *just* fit into the flared mouth enough to be able to seat without falling over.
With lead bullets usually having a width of .356", the bullets are going to get shaved when you seat. Here's a picture of how this happens:
http://www.neverwake.com/treason/PTX.jpg
(NOTE: the lines are drawn exhaggerated in order to show measurements. Relative distances are absolutely not to scale.)
At nearly the top of the PTX's bell, the width is only .356". Barely above this, the edge becomes flat and it is this surface that the case is pushing against to raise the internals up to activate the powder rotor. Getting a measurement on the small bevel is rather difficult as it is incredibly short, but I would estimate about .376". However, I suspect that because the fillet of the cut is so small, it ends up slightly binding against the case and in the process doesn't flare the case mouth any further.
Combined with the linking issues i mentioned above (getting the tolerances as perfect as possible), you'll likely find as everyone else has that your cases are going to flare ~.356" and no more. For FMJ this isn't a problem; for lead, it's unacceptable.
WORTH PURCHASING?
To be fair, the part delivered the result I was after. I can expand in Station 2 and use a powder cop die in Station 3. But I made an ironic observation in the end... which is this:
When charging the case in Station 3, the LNL-AP rotates the shell right around the front and directly below the eyes of the operator. When placing the bullet for seating, it's nearly impossible NOT to notice if you have a charge. In my situation, using HS-6, a doublecharge nearly spills out of the case... even more obvious.
Given this, using a powder cop die - while seeming to add a level of safety - actually seems a bit redundant. Instead of looking into the case, I'm looking at the top of the powder cop die. But now, instead of just keeping my eyes on the case while i place a bullet, it's look up (to the die) and then down again (to place the bullet)... meaning i *still* am looking inside the case either way.
So for $11 (PTX) + $30 (RCBS powder cop die) I've added complexity to the charging system and given up all flexibility (and amount of flare) when expanding the case mouth. I suppose using a complete lock-out die would benefit in this type of situation, but using a visual-only die seems rather pointless when one is still looking at the case along the way.
FINAL VERDICT
The Hornady PTX is only $11, and spending the cash was worth it to satisfy my curiousity. For the moment, I'm going to leave it in the press... it DOES work for my needs, and I'll spend my time reloading instead of putting the press back the way it was... until i load lead bullets, that is.
However: given that the part is caliber-specific, can require substantial setup time, and does not allow the use of lead bullets I honestly don't recommend bothering with it unless you absolutely need to free up a Station.
BTW: MMaP99 is working on a prototype which addresses the problem with lead bullets - when it's ready, I'm standing in line to try it. I've no doubt his solution will be better, given that the factory option drove him to design a new one. ;)
I know alot of people have tried the factory PTX with similar disappointment... but for those that haven't tried it yet, hopefully this will be some good info before you start ordering parts.
thorn
The benefit of having a PTX (powder-through expander) is that it allows you to flare the case mouth in the same station as the powder measure, which can free up another station for a different purpose. In my case, I wanted to use a "powder cop" die in Station 3. Because I seat the bullet in Station 4 and taper crimp in Station 5, the only way to use a powder cop die was to free up Station 3.
INSTALLATION
The part itself is simply a tube with a tapered end, which replaces the powder funnel insert inside the powder drop tube. Replacing the part itself is easy, but unfortunately you may find there's more work needed when it comes to the powder measure.
The (bare-bone) instructions dictate that the powder measure assembly should be screwed into the die until it nearly touches the shell plate. Reattach the arm link and go on about your evening. Presumably, this will cause a full throw of the powder rotor as well as flare the mouth of the shell. However, in my case this didn't happen.
I spent about an hour having to adjust the linkage to the rotor, doing many tests with a shell casing to get the rotor to correctly perform a full up/down rotation. It was absolutely not a "drop-in part", requiring a lot of small tweaks, testing, retweaking, and retesting. Differences of 1/8" - 1/4" were very significant... it took quite a long time to find the optimal position for the link height.
MINIMAL EXPANSION
Once it was finally installed completely, I ran a few shells through and noticed the problem that others with PTX experience have reported. The PTX does not flare the case mouth very much at all... in fact, it is barely enough to do the job. I'm using 124gr FMJ bullets that measure .355" wide, and they *just* fit into the flared mouth enough to be able to seat without falling over.
With lead bullets usually having a width of .356", the bullets are going to get shaved when you seat. Here's a picture of how this happens:
http://www.neverwake.com/treason/PTX.jpg
(NOTE: the lines are drawn exhaggerated in order to show measurements. Relative distances are absolutely not to scale.)
At nearly the top of the PTX's bell, the width is only .356". Barely above this, the edge becomes flat and it is this surface that the case is pushing against to raise the internals up to activate the powder rotor. Getting a measurement on the small bevel is rather difficult as it is incredibly short, but I would estimate about .376". However, I suspect that because the fillet of the cut is so small, it ends up slightly binding against the case and in the process doesn't flare the case mouth any further.
Combined with the linking issues i mentioned above (getting the tolerances as perfect as possible), you'll likely find as everyone else has that your cases are going to flare ~.356" and no more. For FMJ this isn't a problem; for lead, it's unacceptable.
WORTH PURCHASING?
To be fair, the part delivered the result I was after. I can expand in Station 2 and use a powder cop die in Station 3. But I made an ironic observation in the end... which is this:
When charging the case in Station 3, the LNL-AP rotates the shell right around the front and directly below the eyes of the operator. When placing the bullet for seating, it's nearly impossible NOT to notice if you have a charge. In my situation, using HS-6, a doublecharge nearly spills out of the case... even more obvious.
Given this, using a powder cop die - while seeming to add a level of safety - actually seems a bit redundant. Instead of looking into the case, I'm looking at the top of the powder cop die. But now, instead of just keeping my eyes on the case while i place a bullet, it's look up (to the die) and then down again (to place the bullet)... meaning i *still* am looking inside the case either way.
So for $11 (PTX) + $30 (RCBS powder cop die) I've added complexity to the charging system and given up all flexibility (and amount of flare) when expanding the case mouth. I suppose using a complete lock-out die would benefit in this type of situation, but using a visual-only die seems rather pointless when one is still looking at the case along the way.
FINAL VERDICT
The Hornady PTX is only $11, and spending the cash was worth it to satisfy my curiousity. For the moment, I'm going to leave it in the press... it DOES work for my needs, and I'll spend my time reloading instead of putting the press back the way it was... until i load lead bullets, that is.
However: given that the part is caliber-specific, can require substantial setup time, and does not allow the use of lead bullets I honestly don't recommend bothering with it unless you absolutely need to free up a Station.
BTW: MMaP99 is working on a prototype which addresses the problem with lead bullets - when it's ready, I'm standing in line to try it. I've no doubt his solution will be better, given that the factory option drove him to design a new one. ;)
I know alot of people have tried the factory PTX with similar disappointment... but for those that haven't tried it yet, hopefully this will be some good info before you start ordering parts.
thorn