Porter pins vs expander
- Thread starter dbaird
- Start date
Jager
Gold $$ Contributor
Many of us are sold on mandrel-sizing when ultimate precision is desired. Sizing from the top, down generally results in less case neck runout and better potential accuracy, compared to using conventional expander balls.
With that in mind, the choice between a classic expander mandrel, such as a Sinclair, and gage pins a la the Porter solution... comes down to the much finer control over the amount of neck tension you're applying with the gage pins. They both fundamentally do the same thing.
Using an expander ball is a very different way of sizing your neck. It has the benefit of speed. But at the cost of ultimate accuracy.
With that in mind, the choice between a classic expander mandrel, such as a Sinclair, and gage pins a la the Porter solution... comes down to the much finer control over the amount of neck tension you're applying with the gage pins. They both fundamentally do the same thing.
Using an expander ball is a very different way of sizing your neck. It has the benefit of speed. But at the cost of ultimate accuracy.
Keep one thing in mind, the Porter pins are nothing more than standard gauge pins that can be purchased individually from machine tool suppliers such as MSC, Enco, Shars or on Amazon for $4.00-$5.00 each.
ER32 collets which fit the Porter Precision die are also easily available. The collets accept a range of gauge pins so you can easily tune your neck expansion for just exactly the interference fit you want.
The perfect tool for the job.
ER32 collets which fit the Porter Precision die are also easily available. The collets accept a range of gauge pins so you can easily tune your neck expansion for just exactly the interference fit you want.
The perfect tool for the job.
Ned Ludd
Silver $$ Contributor
One difference between the use of a mandrel versus an expander ball is that the mandrel is pushed through down through the neck, as opposed to being pulled out through the neck from the inside after the bushing has sized it down. That may not seem like a big deal. However, I have read many posts here where someone had unacceptable runout and eventually narrowed down the cause to the use of an expander ball. That does not mean an expander ball necessarily induces runout, it simply means that runout may be a consideration when using one.
I have used mandrels from 21st Century for a number of years and been very happy with their performance.
21stcenturyinnovation.com
21stcenturyinnovation.com
There are a few things that might impact my decision of whether to go with a pin gauge set or the 21st Century mandrels, if I didn't currently own either and was starting from scratch. The first would be, how many different sizes did I need? If you want a wide range of different sized mandrels, the push pin sets might be the better option in terms of cost. If you just need a few different sizes, the mandrels and die are purpose-built for sizing/expanding case necks.
The second would be whether it is necessary to modify the taper on the end of the pin gauges. They appear to be tapered, but the taper seems a little more abrupt than that of the 21st Century mandrels. I can't tell from previous posts whether anyone felt it was necessary to modify the taper on their pin gauges, but it would be a consideration if it was. Perhaps someone that actually uses the pin gauges could chime in on whether they're ready to go straight from the box.
Finally, the type of die body used with the pin gauges will not be exactly the same as used with the mandrels. How much (if any) extra effort does it require to install/change one of the pin gauges in a die body, and is it free floating once it is installed? As mentioned, the mandrels are purpose-built for sizing case necks and these considerations have already been taken care of with the 21st Century die body. If, and I repeat, "If", the pin gauges require anything special as far as the die body and installation process, then that would also be something to consider.
I have used mandrels from 21st Century for a number of years and been very happy with their performance.
Caliber Specific Expander Mandrel Kits
Our caliber specific expander mandrels are available in .0005” increments in calibers 22 to 338 and will range from .001” above bullet diameter to at least .003” below bullet diameter depending on caliber. This will allow the reloader to find proper neck tension to fine-tune their loads. The...
21stcenturyinnovation.com
Expander Die Body
Expander Die Body Introducing the much anticipated Generation X Expander Die Body with viewing window! Set up of an expander die has not been easier! The viewing window allows the user to set the die to allow for optimal mandrel use without “bottoming out”. Machined out of 7075 Aluminum and...
There are a few things that might impact my decision of whether to go with a pin gauge set or the 21st Century mandrels, if I didn't currently own either and was starting from scratch. The first would be, how many different sizes did I need? If you want a wide range of different sized mandrels, the push pin sets might be the better option in terms of cost. If you just need a few different sizes, the mandrels and die are purpose-built for sizing/expanding case necks.
The second would be whether it is necessary to modify the taper on the end of the pin gauges. They appear to be tapered, but the taper seems a little more abrupt than that of the 21st Century mandrels. I can't tell from previous posts whether anyone felt it was necessary to modify the taper on their pin gauges, but it would be a consideration if it was. Perhaps someone that actually uses the pin gauges could chime in on whether they're ready to go straight from the box.
Finally, the type of die body used with the pin gauges will not be exactly the same as used with the mandrels. How much (if any) extra effort does it require to install/change one of the pin gauges in a die body, and is it free floating once it is installed? As mentioned, the mandrels are purpose-built for sizing case necks and these considerations have already been taken care of with the 21st Century die body. If, and I repeat, "If", the pin gauges require anything special as far as the die body and installation process, then that would also be something to consider.
K&M expander dies and expand mandrels are top notch. Using them along with Redding competition, full length sizing dies and micrometer seaters, I get sub one-thousandth run-out consistently.One difference between the use of a mandrel versus an expander ball is that the mandrel is pushed through down through the neck, as opposed to being pulled out through the neck from the inside after the bushing has sized it down. That may not seem like a big deal. However, I have read many posts here where someone had unacceptable runout and eventually narrowed down the cause to the use of an expander ball. That does not mean an expander ball necessarily induces runout, it simply means that runout may be a consideration when using one.
I have used mandrels from 21st Century for a number of years and been very happy with their performance.
Caliber Specific Expander Mandrel Kits
Our caliber specific expander mandrels are available in .0005” increments in calibers 22 to 338 and will range from .001” above bullet diameter to at least .003” below bullet diameter depending on caliber. This will allow the reloader to find proper neck tension to fine-tune their loads. The...Expander Die Body
Expander Die Body Introducing the much anticipated Generation X Expander Die Body with viewing window! Set up of an expander die has not been easier! The viewing window allows the user to set the die to allow for optimal mandrel use without “bottoming out”. Machined out of 7075 Aluminum and...
There are a few things that might impact my decision of whether to go with a pin gauge set or the 21st Century mandrels, if I didn't currently own either and was starting from scratch. The first would be, how many different sizes did I need? If you want a wide range of different sized mandrels, the push pin sets might be the better option in terms of cost. If you just need a few different sizes, the mandrels and die are purpose-built for sizing/expanding case necks.
The second would be whether it is necessary to modify the taper on the end of the pin gauges. They appear to be tapered, but the taper seems a little more abrupt than that of the 21st Century mandrels. I can't tell from previous posts whether anyone felt it was necessary to modify the taper on their pin gauges, but it would be a consideration if it was. Perhaps someone that actually uses the pin gauges could chime in on whether they're ready to go straight from the box.
Finally, the type of die body used with the pin gauges will not be exactly the same as used with the mandrels. How much (if any) extra effort does it require to install/change one of the pin gauges in a die body, and is it free floating once it is installed? As mentioned, the mandrels are purpose-built for sizing case necks and these considerations have already been taken care of with the 21st Century die body. If, and I repeat, "If", the pin gauges require anything special as far as the die body and installation process, then that would also be something to consider.
+1 for the Porter pin die. It's what I use.
PopCharlie
PopCharlie
I only use the Porter pin die. I purchase my gauge pins on Amazon and then grind a taper on the end, polishing the surface on completion.
A nice trick I have found is to under size the neck using a 0.002" bushing that is less than the desired end size, then expand to using the pin gauge to the final size. I have also found that holding the case in the die (Dwell) for at least 15 seconds on un-turned necks eliminates any spring back. For turned necks you can get away with as little as 10 seconds. This is for all three sizing operations, FL, Neck and Pin Expansion. Make life easier in a progressive as I am performing all three processes at once on separate cases.
A nice trick I have found is to under size the neck using a 0.002" bushing that is less than the desired end size, then expand to using the pin gauge to the final size. I have also found that holding the case in the die (Dwell) for at least 15 seconds on un-turned necks eliminates any spring back. For turned necks you can get away with as little as 10 seconds. This is for all three sizing operations, FL, Neck and Pin Expansion. Make life easier in a progressive as I am performing all three processes at once on separate cases.
Doesn't that sequence basically produce quite a lot of movement of the necks? In your experience doesn't that "over-work" the brass? (Essentially by adding another +0.004" movement that wouldn't otherwise occur.)
Wondering, as I've got a new Porter mandrel expander die as well.
Good tip, on the dwell time.
I have not had any issues from this process, I anneal on every firing and have gotten up to 26 firings.
Keep in mind that I am under sizing by 0.002" then bringing it back to 0.3075"
The delta between 100 case on the neck is less than 0.0004". I can't complain about that at all. But seems as thought the accuracy suffered once I take them past 24 firings. So that set of cases have been retired. I will probably not use the other sets of cases past 20 firings as I think my accuracy was being effected starting at that point.
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