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Micrometer Seating Dies


Welcome back, reloaders!


Let's get down too it.


I was browsing through Brownells website the other day and decided to try out the famous Forster Micrometer Seating dies and do a review. I've heard a lot of hype around Micrometer dies in general and especially this one.


If you follow any of my social media accounts, you know that I am a big fan of L.E. Wilson and the micrometer hand die. It works phenomenally, so, It's only fair that I put it up against a test!


Before we get down to it, let's break down this Forster Die for you.


"The Forster Ultra Micrometer Seating Die offers a close-fitting, die chamber that holds the bullet and case for their entire length, as well as holds the bullet, case and bullet seating stem in a common axis during the bullet seating operation to ensure match-grade alignment. The sliding die chamber has a concentric bullet channel that is just slightly larger (per side) than the bullet diameter. This tight fit ensures straight line (co-axial) seating. The bullet seating stem contacts the bullet ogive as far away from the bullet's tip as possible." -Forster instruction manual


Forster Die Manual, Die Nomenclature

Sounds pretty awesome, right? I added a photo from the Forster Manual as well so you could better understand how the die operates. Notice the sleeve that is mentioned that holds everything in place from beginning to end for enhanced concentricity.


The only thing I dislike about the die is the locking ring. It is a perfect circumference, so if you plan on using it on more traditional presses and need to unscrew the die, have fun marking up and potentially destroying your locking nut over time. Having the COAX and the ability to set the die and just pull it in and out without having to screw it in is a huge benefit and what I believe, the reason they don't provide more wrench friendly locking nuts. Deal-breaker? of course not. Just me being picky.


Brass Preparation and seating dies


For this test I wanted everything to be fair, so, all the brass was sized the same, using the same die, same bushing, same Forster COAX press, the same concentricity from one piece of brass to the other, once fired, same lot, triple checked, all good to go. I even went so far to make sure that my bushing was concentric as well. Believe it or not, those can be out of wack too.


However, since the L.E. Wilson is a hand die, we obviously can't screw that in the press. So, take the numbers as they are and you make up your interpretations. I have also tested a regular RCBS seating die from their two die set and a Pacesetter Lee seating die to make things interesting.


On another note, a lot of the concentricity will come from resizing the brass properly, to begin with. Everything I have checked lines up the same. If you are interested to read what other factors that can come into play when it comes to the concentricity of your rounds, I'd give this a read: Concetricity factors.


"But why does concentricity matter or what is bullet runout?"

If things are perfectly concentric, it means better accuracy downrange. "Bullet run out simply means the way the bullet “runs out” into the rifling. The ideal desired cartridge concentricity is zero Total Indicated Runout (TIR), measured with a concentricity tool with the dial indicator on the bullet about 1/16th of an inch above the case mouth. If you want to get technical, do the case neck when using military brass, so you can check the concentricity and any variation in case neck walls. Do the measurement on the case neck slightly below the case mouth. Factory loaded match ammunition usually exhibits no more than .0015" TIR, which is deemed excellent."-Sinclair international

"If you load for accuracy, especially for distance shooting; you want no more than .002" to .003". Ammo with a TIR of .005" is used for shorter ranges. If it goes beyond .005", either use it for practice ammo or very short ranges because accuracy will fall off quickly with that kind of TIR. Even M118 7.62 NATO ammo had problems with TIR depending on the lot, from early M118 to M118LR."-Sinclair International



Test

For the first test using the Forster, I used 10 pieces of the already prepped brass. In order, are the rounds and their concentricity checked with the 21st-century concentricity gauge using the same lot of bullets. Unfortunately, with the meter, I can't measure to the ten-thousandths of a measurement. However, most of the measurements under .001 hardly moved from what I could see.


Forster Ultra Micrometer Seating Die Bullet Runout

1. Under .001

2. Under .001

3. Under .001

4. Under .001

5. Under .001

6. Under .001

7. Under .001

8. Under .001

9. Under .001

10. Under .001


L.E. Wilson Micrometer Seating Die Bullet Runout

1. Under .001

2. Under .001

3. Under .001

4. Under .001

5. Under .001

6. Under .001

7. Under .001

8. Under .001

9. Under .001

10. Under .001


Regular RCBS Two Die Set Seater Die Bullet Runout

1. Right at .001 mark

2. Right at .001 mark

3. Right at .001 mark

4. Right at .001 mark

5. Right at .001 mark

6. Right at .001 mark

7. Just over the .001 mark

8. Right at .001 mark

9. Right at .001 mark

10. Right at .001 mark


Lee Pacesetter Seating Die Bullet Runout

1. Right at .001 mark

2. Right at .001 mark

3. Just over .001 mark

4. Right at .001 mark

5. Just over the .001 mark

6. Right at .001 mark

7. Just over the .001 mark

8. Just over the .001 mark

9. Right at .002 mark

10. Right at .001 mark


Final thoughts


The micrometer seating dies can be a great addition to any reloading bench. One might ask, are they an absolute necessity to shoot long range? Of course not! However, if you are like me, I am super anal about the reloading process and I personally like to make sure everything is perfect to limit out every possibility of something going not as planned. Can you use regular dies? Of course, why the hell not. These numbers that I have also acquired can be slightly different too. You can get a slightly "wonky" or an out of spec seating stem from the manufacturer of your choice, usually, it's due to projectile profile, but I digress. It's always good to check things with the proper measuring tools. Overall, micrometer seating dies make seating bullets a breeze and helps a lot with concentricity.



As always, shoot straight, be safe, and happy reloading! If you liked this article and think it was worth $1, here is our Patreon: https://www.patreon.com/Reloadingallday



Blake has been writing reloading articles for three years and helping out within the community to further enhance reloading education. In his free time, he works within the community to help out new hand-loaders by educating them on the many variables that come with this wonderful hobby. His passion is solely based on educating others so that they may pass on that information to future generations, keeping the art of hand-loading alive. Disclaimer: The content you are about to read is for demonstration purposes only. This includes videos, blog posts, articles, and all information associated with this website. Do not attempt anything you see on this website. Again, these are for demonstration purposes only. If you see reloading data and or comments, please refer to the manufacturer of your choice and contact a technician. We are not responsible for any false data or comments from individuals. Again, this is a demonstration for reloading. Please contact or take classes from certified reloading instructors or contact the manufacturer of your choice. Please, do not attempt to tamper or modify with ammunition or firearms. Seek out a licensed professional or gunsmith. Any information you watch or read on this website must be assumed to have an error and should not be performed. Reloadingallday will not and cannot be held responsible for harm caused to readers and watchers. The material that is covered is for demonstration purposes only. Please be aware that hand-loading and other topics covered are very dangerous and you are within full responsibility and liability for your own actions. Reloadingallday is also not responsible or liable for any damage that might be caused due to those who enter this website and read any of our material or watch. Again, this is for demonstration purposes only. By reading this article, you are agreeing that you are responsible for yourself, everyone around you, watchers, viewers, commenters, and fans. You are also agreeing that you are responsible for the safety and property as follows: yourself, everyone around you, watchers, viewers, commentators, and fans. Also, you are accepting that you agree with everything this disclaimer has written down.


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