Couple trimming questions

[chadrp]

Just got my Giraud trimmer and was wondering a couple things.

I size and mandrel to expand. Should I trim before expanding or after? I'd kinda like to trim before so all brass prep is done and cases are just waiting to be expanded, charged and seated.

If I trim before expanding, the case that came with the trimmer measures .2885 and I'm using a .287 bushing so my cases measure .2865-.287. Is that enough difference to fiddle with moving the cutter?
TIA

 

[Dthomas3523]

Not sure what you’re asking as far as comparing it to the bushing. The two things are not really correlated.

If the trimmer gives you the inside and outside bevel you want, run it.

I trim as the last step before prime/powder/seat.

 

[chadrp]

Not sure what you’re asking as far as comparing it to the bushing. The two things are not really correlated.

If the trimmer gives you the inside and outside bevel you want, run it.

I trim as the last step before prime/powder/seat.

I was just comparing my smaller non expanded case size to the case that came with the trimmer that it was set up to in asking if its worth fiddling with the cutter for the .0015 smaller case diameter. The few I did at that size I didn't think looked to bad but not as nice as the one sent with it but im sure i need to develop a little technique with it..

If i would trim after expanding the case diameter would be closer to the diameter of case sent with it.

 

[straightshooter1]

I always trim with my Giraud as the final step in my case preparation . . . except when I turn the necks, then turning is the final step with trimming just before that.

 

[femadog]

Just got my Giraud trimmer and was wondering a couple things.

I size and mandrel to expand. Should I trim before expanding or after? I'd kinda like to trim before so all brass prep is done and cases are just waiting to be expanded, charged and seated.

If I trim before expanding, the case that came with the trimmer measures .2885 and I'm using a .287 bushing so my cases measure .2865-.287. Is that enough difference to fiddle with moving the cutter?
TIA

I haven't seen much difference when trimming mine but I always trim after sizing (required) but before the mandrel. It will be consistent with the same brand cases for a while but case wall thickness will impact the bevels more than the order in which I trim so Lapua will be different than Winchester. As long as I have consistent length and a bevel on the inside and outside of the case mouth all the way around, I move on. In my my experience, the spin you put on the case as you trim has as much effect as anything and I have trimmed thousands of cases over the years, mostly 223 and 308 for High Power competition.. YMMV

 

[spife7980]

When I expand mine I still have the lanolin lube inside of the necks. I then tumble and when they are clean I will run them through the trimmer. Then a brushing to make sure its all kosher.

There will always be that bit of difference in the chamfer/deburr dividing line between expanded vs nonexpanded when trimmed, or different chamberings of the same caliber, or different brass in the same chambering. I set it perfect for one and then the next variations will generally will be pretty close, maybe it needs a smidge to the other way, Ill adjust to accommodate and then its usually pretty settled into that happy spot of compromise. You only have like .013 of total neck thickness to work with so if you want to divide chamfer/deburr in half you have a few thou of space there in the middle where it should accommodate all of the different variations possible inside of the same caliber cutter while still giving a satisfactory result.

 

[Sig Marine]

I set my Giraud up to trim after sizing so the chamfers are consistent. In your case, it probably doesn't matter as long as you perform the trimming in the same sequence of case prep every time. Once the case is sized, the necks should all be the same diameter. After you run a mandrel through them, they may be a different diameter as sized but they all will be of a same diameter.

 

[chadrp]

Thanks guys, that helps but kinda leads to another related question I was thinking about in determining where to put trimming in my reloading process.

Do you see seating issues if you leave your expanded brass sit unloaded for an amount of time before charging and seating??

I've heard that if you expand the brass you should seat a bullet in it, like the same day, or it can shrink back up if you let it sit for awhile leading to inconsistent neck tension.

I'd just like to size and prep a bunch of brass at once but not load it till I'm getting low on ammo in case I want to make a change, so just trying to determine where in the process I can let it sit and not have a ton of steps left when time to load. Thanks

 

[straightshooter1]

One of the reasons I anneal after every firing is so that there is less spring back . . . especially over time. The more work hardened the more spring back one is going to see and yes, over time (like 24 hrs) one is going to see some spring back, which will effect "seating resistance", not "neck tension". I'm after consistency, so whether the seating resistance is less or more from one batch to another isn't as much a concern as from cartridge to cartridge. I find that by annealing often provide has been key in getting the consistency where I don't really notice a difference in seating when my processed cases have been sitting around for a while (like I process about 200 cases at a time and fire 50-75 per week).

When you referred to neck tension, I assume you were actually referring to seating resistance???

 

[Sig Marine]

I prep my brass to the point it is ready to load; meaning cleaned, annealed, sized, trimmed and primed. After that, I don't worry about it and they get loaded when they get loaded. The only feedback I get is from the targets and chrono numbers; I load for 10 rifles and have ES's between 15-25 fps and SD's of 3.1-8.2 fps with most having SD's of between 5-6 fps and my samplings are from at least 20 shot strings without culling for effect. I do use "dry lube" when seating bullets to help with seating and release consistency.

I know shooters who believe they get more consistent neck tension when letting their brass sit at least a week or two after sizing to let the brass "relax" before loading. To be honest, I have more of a concern with loading rounds and having them sit for an extended length of time and the possibility of "cold" welding of the bullet to the case thus causing inconsistent "release". I know many shooters who seat long and then seat to final depth just before use to make sure the bullets are not stuck in any way.

 

[chadrp]

When you referred to neck tension, I assume you were actually referring to seating resistance???
Yes, that would be correct. I
Seating resistance inconsistencies, which I would assume could lead to velocity inconsistencies?

When you referred to neck tension, I assume you were actually referring to seating resistance???

Yes, that would be correct. I guess I was thinking more resistance equated more tension which probably isn't the way to equate it.

 

[chadrp]

I prep my brass to the point it is ready to load; meaning cleaned, annealed, sized, trimmed and primed. After that, I don't worry about it and they get loaded when they get loaded. The only feedback I get is from the targets and chrono numbers; I load for 10 rifles and have ES's between 15-25 fps and SD's of 3.1-8.2 fps with most having SD's of between 5-6 fps and my samplings are from at least 20 shot strings without culling for effect. I do use "dry lube" when seating bullets to help with seating and release consistency.

I know shooters who believe they get more consistent neck tension when letting their brass sit at least a week or two after sizing to let the brass "relax" before loading. To be honest, I have more of a concern with loading rounds and having them sit for an extended length of time and the possibility of "cold" welding of the bullet to the case thus causing inconsistent "release". I know many shooters who seat long and then seat to final depth just before use to make sure the bullets are not stuck in any way.

Thats interesting, I hadn't thought about seating long and then final seating to length. I'm sure most of this is beyond what I need in terms of acceptable accuracy when I still need to work on wind calling but if I'm gonna reload I just as well try and learn to do the best I can.

 

[Sig Marine]

While the forum is a great place to get started, testing on your own to see what "makes a difference" is the only way to have confidence in what you're doing. As with shooting, I trust no one's information. I range my own targets, call my own wind, spot my own impacts, make my own corrections, etc. It's all on me and when something goes wrong, I can look back and make adjustments based on information I processed and not guess on whether or not someone gave me bad Intel.

 

[chadrp]

While the forum is a great place to get started, testing on your own to see what "makes a difference" is the only way to have confidence in what you're doing. As with shooting, I trust no one's information. I range my own targets, call my own wind, spot my own impacts, make my own corrections, etc. It's all on me and when something goes wrong, I can look back and make adjustments based on information I processed and not guess on whether or not someone gave me bad Intel.

I 100% agree. Its great to see and hear ideas on how others do it, but I have been starting to shoot better since I quit asking for wind and started making my own calls and learning how to fix it. Thanks!

 

[Hussell]

Just make sure to keep it the same. Small sample sizes but I have tested size trim mandrel vs size mandrel trim and had different speeds and sds when changing the order of the steps.