Trimming tips?

skipglo

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Joined
Jan 23, 2015
Messages
2,529
Location
Alberta
How often do you trim?

Do you trim to saami minimum?

How much do you let brass grow before trimming again?

What is your acceptable level of length variation when trimming?

Any other tips or tricks?
Get a Forrester electric...set once...trim everytime...some won't need it some will...takes a few extra minutes for guaranteed consistency on brass!
 

Ucsdryder

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Jan 23, 2016
Messages
337
Get a Forrester electric...set once...trim everytime...some won't need it some will...takes a few extra minutes for guaranteed consistency on brass!
I’m so tired of spending money to save money reloading!!!!! 😂

Zero money has been saved and any money that might be saved will be shot down the barrel of my rifle because apparently once I have the components they’re “free” and I should go shoot them.
 

skipglo

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Joined
Jan 23, 2015
Messages
2,529
Location
Alberta
I’m so tired of spending money to save money reloading!!!!! 😂

Zero money has been saved and any money that might be saved will be shot down the barrel of my rifle because apparently once I have the components they’re “free” and I should go shoot them.
Forrester is just another expense....saves nothing...except time...and time is Money! So...just keep spending....can't take it with you ...and when you're gone.....someone can inherit it FREE and really save money!😅 And if you really aren't saving....sell it all and buy Factory....oh yeah....aren't any.... or components right now....so you are saving money.....lol
 

Oldtime Shooter13

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Joined
Mar 8, 2019
Messages
69
Location
Maine
I am not a fan of trimming! It is a necessity, but not a must do until your reach Max Case OAL. I measure to make sure my fired/sized cases are within a tolerance each firing. If you are shooting the 30 or 40 degree shoulder cartridges then you will trim much less. One of two reasons I changed fro 243 Win to 6 CM. The other is factory twist rate in 6CM. Another discussion!

I shoot the same cases for load development over and over. I trim when they start reaching max case length back to min case length (SAMI). I always 30 Degree chamfer inside case mouth and desire outside case neck. If I am shooting the same cases with the same charge my cases rarely grow more that .001 if at all.

The only cases that I am very fussy about is 45ACP. This Cartridge headspace off of the case mouth and must be as near perfect as you can get. Hate trimming 45ACP, but it is a must.

Lastly strait wall cases is also important to have case OAL the same due to crimping. You also must use caution to not allowed to grow into the forcing cone! Pressure can become erratic and cause spikes.

I use LE Wilson trimmer on everything except 45
ACP. Pain in the butt to trim 45 ACP in LE Wilson! I use my old Lyman trimmer for 45 ACP.
 

Oldtime Shooter13

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Joined
Mar 8, 2019
Messages
69
Location
Maine
I am not a fan of trimming! It is a necessity, but not a must do until your reach Max Case OAL. I measure to make sure my fired/sized cases are within a tolerance each firing. If you are shooting the 30 or 40 degree shoulder cartridges then you will trim much less. One of two reasons I changed fro 243 Win to 6 CM. The other is factory twist rate in 6CM. Another discussion!

I shoot the same cases for load development over and over. I trim when they start reaching max case length back to min case length (SAMI). I always 30 Degree chamfer inside case mouth and desire outside case neck. If I am shooting the same cases with the same charge my cases rarely grow more that .001 if at all.

The only cases that I am very fussy about is 45ACP. This Cartridge headspace off of the case mouth and must be as near perfect as you can get. Hate trimming 45ACP, but it is a must.

Lastly strait wall cases is also important to have case OAL the same due to crimping. You also must use caution to not allowed to grow into the cylinder too far! Pressure can become erratic and cause spikes.

I use LE Wilson trimmer on everything except 45
ACP. Pain in the butt to trim 45 ACP in LE Wilson! I use my old Lyman trimmer for 45 ACP.
I need to make a correction. I meant to warn about letting brass grow into strait wall cylinder not the forcing cone.

Shows that one should proof read post before posting it? I plead Old Age Syndrome, works for POTUS!
 

isaaccarlson

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Joined
May 11, 2011
Messages
185
Location
NW Wisconsin
I have a lee target loader, and it has a trimmer, so I just trim every case. It's easy and fast and I don't ever have to worry about how long my cases are.
 

Lenny Foffa

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Joined
Mar 6, 2017
Messages
524
I measure my cases after each resizing. For my 270 Win MAX case length for me is 2.540 the SAAMI max for that caliber. When ever that length is reached , I trim back to 2.535, with one of my Forester Case Trimmers. Some times I may reload the cases 3 or 4 times before they require a trim . I think the case streching comes from expander ball of the sizing die squeaking in the case neck , as I pull the case down out of the die. I think the answer is polish the expander ball or get Bushing Dies !!!
 

WiscGunner

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Joined
Aug 2, 2016
Messages
223
I trim my cases for uniformity as long as it is under max. Might get a bore scope to play with but I measure my brass into groups, ignore the shortest fliers and trim everything down to the shortest large group so they are all consistent for neck tension. I then leave this as my trim length and trim each reload with a Giraud Power Trimmer
 

340PR

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Joined
Nov 18, 2018
Messages
111
Location
Tennessee
A lot of good info above.
Set up the process that matches your equipment, and do the same every time. Consistency is what I am after. Does any one operation drastically affect accuracy? Most likely not. However if you don't do each step every time, you will start to see variation, and won't know how to fix it. Also, it depends on how far down the rabbit hole you care to travel.
That said, I anneal, size, trim, chamfer in and out, brush necks, and clean primer pockets, each firing. I have invested money in motorized equipment to make the process fast and accurate, so it takes about 1.5hr to fully process 100 rounds of brass, including wait times.
1. I trim enough to leave .010" to end of chamber (as close as I can measure). chamber lengths can vary quite a bit from Min to max SAAMI not even accounting for custom chambers. BUT, you must trim enough for the neck to expand, or you can over pressure your firearm, which is dangerous (thus SAAMI specs). Proceed carefully and with knowledge with custom chambers.
2. Small cases (6BR, Grendel, etc.) don't grow much (.0005" +/-). larger cases can grow over .001" per firing.
3. Trim length variation; as close as my equipment allows (depends on how good a job I do on sizing, as trim is based off of shoulder). Usually within .001" overall case length.
4. Chamfer very little; usually 1 to 1.5 revolution with light touch against motorized cutters (just enough to insure the sharp edge is off of ID and OD).
End of the day, you most likely will not see an appreciable difference shot to shot if you do it all or none if you are not applying precision to the rest of your processes.
 

kfreeze

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Joined
Apr 9, 2014
Messages
542
Location
cambridge, mn
How often do you trim?

Do you trim to saami minimum?

How much do you let brass grow before trimming again?

What is your acceptable level of length variation when trimming?

Any other tips or tricks?

I use these to see my max length and then keep hunting rifle cases at least .010" shorter and benchrest tight chamber type stuff at least .005" shorter.
 
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