Newbie case trimming questions

[dmftoy1]

Ok, first time reloading bottlenecked cartridges. I've got a pile of LC 5.56 brass, FL sizing die, and a case trimmer (and a primer swage). I've FL resized the brass and started trimming a bunch of cases. So now for the questions:

1. How "exact" do you keep the cases in relation to one another? I found that I threw about 50% of the first 10 out and then got everything well adjusted and then got into a groove. I was shooting for a trimmed case length of 1.751 but ended up with some at 1.7515 and some at 1.751. How important is it to be exactly the same? I'm not looking for benchrest accuracy. If I can do as well as or slightly better than the XM193 that I'm currently shooting then I'll be tickled pink.

2. Do you measure each case you trim? I was doing that last night and it doesn't seem to add much time to the process but I'm just curious.

3. Do you need to trim each time you reload them or does a trimming last for 2-3 firings? (If the "hotness" of the load matters, I'm intending to be slightly less than the standard XM193 loading which I believe is pretty hot). Say I'm shooting for 2800fps or so with a 55fmj. Also, I know about the X-die, but I'm wondering about trimming wrt to using a standard die.

Thanks in advance for any advice.

Regards,
Dave

4.

 

[Arch]

Hey Dave,

What are you using to trim your cases? If you just use something like a Lee case trimmer, where you physically can't trim past the case gauge, they will all come out the same length.

Cheers.

 

[dmftoy1]

I'm using a Lyman Universal Trimmer that I picked up on Ebay. It has a "stop" that you adjust to keep you from overtrimming and I think I've got it dialed in, but there still seems to be some variation (very slight) from when I stop seeing anything coming off the case.

Regards,
Dave

 

[Dave P]

Dave, worring about 223 OAL to four decimal places will lead to an early death

Try this: set your trimmer to about 20 mil short of the book value, and trim away. Maybe check the legth after 3-4 firings.

I never trim or check my 200 yrd loads, and only sometimes check my 600 yard loads.

 

[Lennyjoe]

I use the Lee trimmer for each specific cartridge. That way there is no chance of short trimming brass.

 

[dmftoy1]

Dave, worring about 223 OAL to four decimal places will lead to an early death

How do you get away with never trimming your 200 yard loads? I thought if they were over max then you HAD to trim?

Regards,
Dave

 

[Arch]

I'd say it's a good idea to trim them when they grow, if not for anything else, but for safety reasons.

I'm not too sure how fast rifle brass stretches, but the main concern is that the case gets too long, and not only has difficulty in chambering properly, but starts putting the projectile onto the rifling, increasing pressure.

Mabey this is the extreme, but I, like you, just play it safe.

 

[TooTaxed]

Suggest you set your trimmer for 1.75 (or 1.745) and check your trimming process to see why you are getting some longer...I keep trimming until no more shavings come off the cutter and all have fallen clear. Then quickly check the cases against a case length guage or caliper the next time you reload them. Most will probably be OK...any that need trimming will trim very quickly, as you won't have to take much off... Some slight variation is OK as there is a range of acceptable chamber dimensions on the rifles. You can try a few cases with slightly different lengths in your rifle for fit...the action should close easily.

Remember that over all cartridge length (nominal 2.26", slightly different for some bullet shapes) is important. Your best accuracy will be with bullets seated .005 short of the barrel lands, or slightly further away. Therefore bullets with cannelures won't necessarily match your trimmed case mouths exactly.

 

[Rockstar]

Yeah, don't hyperventilate over a few thousandths difference in case length. If you're not going to crimp, case length isn't that critical, anywho. As to a case that's a little too long putting the bullet into the lands, how about an explanation for that one? I don't see that case length has too much relation to o.a.l. If you're seating @ 2.260", that's going to be the o.a.l., regardless of differences in case length.

 

[The Bushmaster]

Rockstar is correct...Just pay attention to your head space. Don't let those cases get too long...

 

[30Cal]

+/- 0.002" is fine. I use a Lee trimmer so I don't measure any of them. If I had something else that I had to set, I would measure the first one. I trim every other firing for 30-06 and .308--.223 will probably be about the same.

Ty

 

[P-32]

I trim my match 308 and 223 after every re-size. I use a Forster which is right next to my press. Quick and easy. I found you have to be uniform in the way you turn your handle.

Like others said, don't go gray over a fraction of thousand of an inch or two.

 

[dmftoy1]

Thanks guys! I finished my first batch of LC cases and it's sitting next to the primer pocket swage now. I think I had 8 hours invested in trimming when it was all said and done. Next time I will be investing in a power adapter.

Have a good one,
Dave

 

[30Cal]

Thanks guys! I finished my first batch of LC cases and it's sitting next to the primer pocket swage now. I think I had 8 hours invested in trimming when it was all said and done. Next time I will be investing in a power adapter.

If I had to spend 8 hours trimming cases, I'd probably swear off shooting rifles for life. Get the power adapter. Unless you only trim 5-15 cases in a sitting, I wouldn't even consider buying a case trimmer unless it can be driven with a motor.

Ty