Cutting cases for 300 AAC for the first time.  I ordered the Elite 3D jig.  Installed it on my HF mini chop saw and now I'm having a hard time getting straight and to the proper OAL.  I've adjusted it half-dozen times and still not getting uniform results.  I'm shooting for 1.38 OAL but they are coming out all over the place.  1.369, 1.388, etc.  Plus they seem to be at a VERY slight angle.  We're talking less than a degree but they are able to move in the calipers so it tells me not perfect.  

Will deburring/trimming take care of the imperfections?  If not, what's the trick to getting this to cut perfectly straight and to the correct OAL??  Seems like a fool's errand as neither the saw nor jig seem to be precision instruments.  

Please share your thoughts, suggestions, and experience.

Thanks!

Thanks for the link.  I posted the question there.

Paging my way back in the thread to see if/when there's already any advice on it.


EDIT:  Wait a min....it looks like you're cutting all the way up at the neck/shoulder.  It looks like you are using your case trimmer at the last step to get to the proper OAL case-wise.  Am I correct or am I seeing things wrong in that pic?   If that's the case, then I really don't need to worry about getting the cases perfect with the chop saw.  Seems like the rest of the process would hone to perfect results.  Thoughts?

I don't know why you would do it any other way than in that pic. Logical progression to a perfect result.

The chop saw should be just for rough cutting the cases (long) & removing the 5.56 neck section. OAL should be set with a case trimmer much later in the process.

This.

The case will grow about 0.008" when you neck it down anyways, so you would have to intentionally cut the cases that much too short in hopes it would grow to the correct length uniformly, which is not reality.

I try to get as close as possible, then when I anneal and resize I only have a little bit left to trim off using my Giraud.

Ok, that makes sense.  

So basically just rough cut the funnel off and then use the trimming to get it to the proper OAL.  MUCH easier.  Still means measuring each case after hitting the trimmer but still....a lot less nerve racking.  

Appreciate the confirmation!!

What kind of trimmer are you using?

I never measure every case, ever.

Assuming your resizing operation is uniform, your trimming step should yield uniform results.

In other words, if you have a trimmer that determines the oal based on the shoulder (like the Giraud or WFT), then as long as all the shoulders are at the same spot all of your trim lengths will be identical.

Unless you're loading precision rounds (not sure why you would on a 300blkout), there's no need to have lengths within a thousandth. In fact, as long as it's not too long or too short to chamber properly I consider it good enough.

My trimmer is a drill bit.  I think Lee makes it.  Is there a better option that will guarantee uniformity?

Thanks

Several.  I use the RCBS Trim-Pro.  Even Lee makes one better than your current option.

I'll have to look into the Trim-Pro.  I think the main perk I'd look for is the ability to pre-set OAL.  

Thanks

There's absolutely tons of trimmers out there.

The top tier ones are Giraud, or if you have one specific caliber the Giraud triway, or the henderson precision trimmer.

There's also the worlds finnest trimmer (WFT). All of those index off the shoulder.

Then you have the lathe style ones like the rcbs trim pro, the Hornady lathe, and the most precise lathe is the Wilson trimmer.

There's also press mounted options like the Dillon trimmer.

There's pros/cons for each style, you just have to weigh the price vs speed vs accuracy. All of these options are better than what you're currently using, but they're also all more expensive... some of them orders of magnitude more expensive.

Doesn't the Lee trimmer have a length guide in it?

Is it missing that part?

The trimmer comes with the kits, but doesn't include the cartridge length guides for it.

https://www.grafs.com/catalog/product/productId/7867

https://leeprecision.com/case-conditioning-tools/case-trimming-tools/

https://leeprecision.com/case-conditioning-tools/case-trimming-tools/case-length-gauge-holder

https://leeprecision.com/gage-holder-300-aac-blackout.html

https://leeprecision.com/cutter-lock-stud.html

To be honest, I'm looking for the easiest to use and most durable trimmer that doesn't break the bank.  Drill powered with the option to hand crank if need be.  Looks like the Lyman Trim Pro (2??) may work.  Not one of the ones you mentioned but any experience with it?  

Thanks!

I bought mine like 15yrs back.  It's literally a little disk with blades on it that goes into the chuck and spins.  I was just using calipers to measure after every few rotations.  Took a LOOOONG time to get it sized right if memory serves.  

I just want something to set and then do 50-100 cases without much thinking.  

Thanks

The trim pro is by rcbs. I know a lot of people like it, but I would add the tri way trimmer head for it.

Attached File



When you need to trim, there are three operations that have to be (arguably) performed. I say arguably because not everyone deburrs because wet tumbling after you trim can deburr some and may require you to skip that step.

You need to cut the length correctly, but that creates square edges. So the next two steps chamfer the inside (so when you seat the bullet it doesn't shave off some of the bullet jacket) and deburr the outside (so it chambers properly).

Here's a before and after the chamfer/deburr steps
Attached File


The best trimmers will do all three of those operations at the same time. The Giraud, Giraud triway, etc, but that's why they can be really expensive.

Getting a cheap trimmer like the Lee is fine, but it will require you to handle each piece of brass 3 times to perform each function. Not only does that take forever, it will destroy your fingers if your bulk processing.

Only you can evaluate what is most important between speed/ease and cost.

Hmm, that's odd.  I was watching FortunCookie45LC and could have sworn the trim pro was Lyman but obviously I was mistaken.  

I'm a BIG fan of buy once cry once.  At the same time I'm not dropping $500-$1k on a trimmer.  Not sure if that is the direction this is heading.  But yeah.... I want high value, not necessarily super cheap.  I can see how only having a drill bit trimmer may give off that vibe but the budget/mindset has grown since then.

Thanks

It all depends on what you need. If you only load 300AAC in bulk you could get a devoted trimmer like the Giraud tri way for $99 and it's about the best you can get with regards to speed and price.

However it's only good for one caliber, so not universal.

If you need to trim 10 calibers you would be better served with the original Giraud, but you're looking at a huge investment.

Something like the Trim Pro with the tri way trimmer is pretty fast, but way cheaper. If you prioritize price over speed/comfort that's a great option.

I personally have a Giraud for the 10+ calibers I reload for and a Wilson trimmer for my precision stuff. I have two young kids and reloading is my primary hobby, so for me it was worth the extra price for the massive speed increase. That's only a choice you can make though.

One thing is for sure, your gun doesn't give a shit how much the trimmer cost to cut the cases as long as they're trimmed properly.

I used the Lee trimmers for about the first 4 years I reloaded and they served me perfectly fine (albeit slow).

The calibers I reload are a bunch of pistol but then in rifle.... .223, 300 AAC, .308win, x39, and 50bmg.  So no plans to buy a different trimmer for each of them.  

I'll check out the Giraud.

EDIT: Yeah no...not spending $500 on a trimmer at this point.  If I increase volume significantly,  then it'd definitely be something to consider.  

Thanks