Trimmer pilot question


AK Eggy
January 26, 2010, 01:19 PM
I tried recently to trim some .44 mag and 9mm brass. The .44 brass was sized by myself and someone else and both of us ussed RCBS carbide dies. trimmed the 9mm brass again using RCBS carbide dies.

When I tried to trim the brass, the pilots for the trimmer were EXTREMELY tight in the brass. So much so that trimming wasn't really possible. I had to remove the pilot from the trimmer to get a better grip on things to be able to get the pilot out of the brass. My trimmer is a Forster and I also tried a new RCBS.

Any ideas what I did wrong and why the ID of the brass is too small for the trimmer pilot? I checked and double checked the pilot charts for both the Forster and RCBS trimmers to make sure I was using the correct pilot. When I queried Forster for the problem with the .44 mag brass, they suggested I send a couple of cases as well as the pilot and they would machine the pilot down to match the brass. I'm thinking that's something I don't want to do as the tooling (sizing dies and trimmer pilots) should be a standard dimension.

The brass is mixed mfg. I've measured the ID of the brass and the OD of the trimmer pilot and it measures just as you would expect with the tight fit, so I don't think it'san alignment issue with the trimmer.

Thanks for your help...

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January 26, 2010, 01:51 PM
Did you champfer the case mouths?
Sometimes the reminent of the old crimp makes the case mouth slightly smaller, even after sizing.

Mixed brass may also present problems due to variations in neck wall thickness.

I make most of my own trimmer pilots.
Those I didn't make have almost always needed a slight reduction in size.

You can do it yourself by chucking it in an electric drill and spinning it with some 400 grit black emery paper.


January 26, 2010, 02:16 PM
Ditto. make sure the crimp is gone, even if you have to expand them slightly and resize.

I have had to polish down some pilots as well.

January 26, 2010, 05:37 PM
I have found that when resizing pistol brass, it is sized inside the case smaller than the pilot. Unlike rifle brass where the neck is expanded to the proper diameter when sized. I readjust the expander die so it doesn't bell the mouth and then trim. Works a lot better that way. If you resize and don't expand, the inside of the case is undersized.

AK Eggy
January 27, 2010, 04:17 AM
I tried expanding some tonight, even so far as to flare the case just a little as if I were ready to place the bullet and still no go. Took the expander out of the die and it measured ~.4255...I measured the pilot OD and it measured the same.

Looks like I need to reduce the size of the pilot. you have a lathe at your disposal, or do you make your pilots some other way?

Thanks for everyone's help.

January 27, 2010, 12:40 PM
Naw, I have a little hobby lathe right now.

Before that, in my former working life, I was some sort of machinist of one kind or another, or manager most of the time, with access to all kinds of lathes.


March 26, 2010, 04:22 PM
I'm having similar issues with .45 ACP brass as AK Eggy had with his 44. mag & 9mm. Though I'm noticing it varies from manf to manf. I thought I had the wrong pilot. I need to do some measuring tonight and I'll report back but here's what I've seen so far:

Brass is clean, decapped and resized using a Lee single stage press. I'm using a Forster Original trimmer, trimming by hand using a .452 pilot (.452 is stamped on the face)

Winchester brass - none to very few issues. Pilot enters and leaves the mouth easily
Remington brass - ditto as with the Winny
Federal - a pain in the butt. I ran it through my resizing die again thinking I forgot but still a pain to get in and then out. It all went into my "toss it" bag
Speer - OK but tight
CCI and other misc brass I've picked up (for plinking) - I tossed it too.

Based on the replies above I should:
1. measure the pilot
2. take apart my die and measure it
3. flare the mouth more for certain brands of brass (?). I'm a "set and forget it" guy - though I do spot checks at all stages every 5 or 10 rounds.
I'm not throwing water on the other brands but I'm thinking if Winny and Rem work why buy/use other stuff. I'd like a simpler solution - brass is brass and if can be used I want to. Its the "green" in me (and I'm cheap too)

Another question about the Forster - when trimming my .45 brass I use almost the entire shaft length to reach the case. It would be nice to move/adjust the collet end closer by even a 1/4". I'm sure all know the trimmer can be adjusted to handle longer cases but it would sure be nice to shorten it just a bit for pistol brass. Its a champ for my .30-06 and .30-30. I've thought about drilling another hole in the base but my shop isn't as "tricked out" as some of yours are. Thoughts? Start another thread?

March 26, 2010, 04:43 PM
The biggest question is, why are you trimming 9mm & .45 ACP brass in the first place??

You need to trim revolver brass to get a consistent roll-crimp.

No need to trim straight-wall pistol brass because you are going to taper-crimp them and "exact to a gnats azz" length is not critical at all.

I have never trimmed any pistol brass in the last 48 years I have been reloading it.


March 26, 2010, 04:56 PM
hmmmmmm. thanks RC. I need to have a conversation with someone. It was his "firm belief" that any brass put into a 1911 style handgun needed trimming to exact, same length to facilitate proper chambering between each round.

March 26, 2010, 04:59 PM
Received a new case trimmer with multi-pack pilots for Christmas. Of the two rifle pilots and one pistol pilot I've used, all were too tight in my sized rifle and .357Magnum pistol brass. I had to chuck them up in my drill and file and sand them to get them to fit inside without being so tight that you couldn't turn the trimmer handle or so tight that they left polished marks inside the mouth of the case. I only trim my .357 and .44 Magnum pistol brass because I want a consistent roll crimp with them. For other cases such as 9MM, 40SW, 45ACP, I don't trim them at all. I do measure all straight walled pistol cases that headspace on the case mouth, just to make sure they are within the minimum and maximum lengths. For 9MM, 40, and .45ACP I taper crimp them and overall length isn't critical.

March 26, 2010, 05:09 PM
It was his "firm belief" that any brass put into a 1911 style handgun needed trimming to exact, same length to facilitate proper chambering between each round. Then he would be wrong.

As noted above, I have been reloading since 1962 and have yet to trim the first straight-wall pistol case. I have loaded .32 ACP, .380 ACP, 9mm, .40 S&W, .45 ACP, and others for a very long time and they do not need to be trimmed, period.

Proper chambering is determined by bullet design, loaded OAL, and proper taper crimp returning the case to correct diameter.
Nothing more.


March 26, 2010, 05:11 PM
Thanks RC. And thanks rg1. Life, and reloading, just got a whole lot simpler.

March 26, 2010, 05:15 PM
I made this pilot for an RCBS trimmer the other day. My .352 pilot was a bit too tight for one batch of roll sized brass I traded for, so I made this one .346.

The easy thing to do is get a second factory one, chuck it in a drill press or drill, and polish it down.

dagger dog
March 26, 2010, 05:52 PM
The pistol dies do not have an expander ball on the decap stem (at least all my Lee's don't) so the brass is not pullled up from the force of the expander ball against the inside of the case neck, that is being held against the inside of the die. Thats what causes most of the stretching.

The practice of trimming your brass when it is new from the bag is not a bad idea, to get all in the same length for ?repeatability? if nothing else, after the initial trim none else is needed.

The problem of the piolt not entering the case on once fired .44 brass is from the crimp and is a fault of NO EXPANDER BALL die.

AK Eggy
March 27, 2010, 04:05 AM
I ended up mounting the pilot in the drill press and polishing it down to get it to work. Once I did that, no more problems.

196....Forster has a shorter base that will facilitate your smaller brass if you still want to trim them. I don't know though if it is too short for rifle brass.

I'm new to this whole thing and didn't even think about the pistol die not having an expander ball until Randy mentioned it in this thread. Seems to me as though that is exactly the issue I was having.

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