Finer points of brass prep for precision loads.

[agent_mango]

I have some questions about the particulars of prepping fired brass between reloads. My rifle is a Savage 223.

The gear I have:
Lyman Tumbler
Lee Dies: Universal Deprimer, Full Size, Neck Size, Seating Die
Redding Body Die (will buy soon)
Lee Trimmer and Chamfer Tool
Sinclair Primer Pocket Uniformer
Sinclair Flashhole Reamer

I have lots of once fired (in my rifle) winchester brass of which I've been using some, and I'll also start to play around with Lapua brass. Right now I'm consistently getting 0.5-0.7 inch 5 shot groups (edit: at 100m) with mag length seated 69 gr SMKs, 24.4 gr Varget, CCI BR4, nonsorted win brass.

So here are my questions in no particular order:

1) I'm worried that operations such as trimming/chamfering and using the flashhole reamer might throw the neck sizing off, but I often find these operations are recommended to be done after neck sizing. Do you do them before or after neck sizing?


2) How important is it to have uniform brass length? My win thrice fired brass (trimmed after the factory firing) has an OAL ranging from 1.749 to 1.754, and the new lapua brass is about 1.750 to 1.752.

I'm worried that different lengths of brass leads to different amounts of neck gripping area on the bullet, which will give shot-to-shot inconsistent neck tension.

Is it just better to trim after every firing, or is a couple thou difference unimportant? (Although I'm unsure as to how small a range of lengths the lee trimming system will give anyway.)


3) After a particular firing, if I don't trim but I do do the standard neck sizing, should I rechamfer the inside of the brass neck (to ease bullet seating) or is it unnecessary?


Thanks for your thoughts!

 

[sunray]

"...consistently getting..." At what distance? Mind you, I wouldn't change anything you're doing. .5 to .7 inches is just dandy.
Relax. Loading match grade ammo is a consistency thing. It's not difficult. Cases all the same, each powder charged weighed and a consistent bullet seat. Considering the consistent groups you're getting, you're doing everything just fine. That's the important part. Consistency in everything.
1) Measure your cases every time, but you won't need to trim every time. Trim when they get to or longer than the max case length. If you trim you'll have to chamfer the inside of the case mouth and deburr the outside. Just enough to get a bullet in the case mouth and remove the burrs created by trimming. The chamfering tool does the deburring and the case mouth chamfering.
The flash hole reamer won't do anything to the neck. It's for the truing and having a consistent sized primer flash hole. It's a one time thing only. Mind you, for most match ammo it's not really necessary.
2) Having the cases all the same length is important. Keeps the OAL the same. However, a few thou for non-bench rest target shooting won't matter too much.
3) You don't need to chamfer or deburr unless you trim.
You can go really nutso and weigh the cases and the bullets too. Use powder from the same manufacturer's lot. These are bench rest techniques though. Bench rest shooters will go as far as determining the powder capacity of their cases. Literally filling the case with water and weighing that. You don't need to do any of it for regular target shooting and you'll still be shooting your high quality ammo.

 

[agent_mango]

I edited my post to reflect that the consistent 0.5-0.7 inch 5 shot groups are at 100 meters.

The thing that made me mention the flashhole reamer is that the tool body touches the neck when you have it inserted. It probably is a one time only thing but I'm going to try and check with brass fired again after already having it done to see if the flashhole has gotten a little smaller.

Yeah I don't have the time or energy to go super nutso! Nor do I care about benchrest levels of performance. But I'm just curious if there's stuff I can do to get me groups a few points smaller in size.

 

[maynard]

If you are using non Lapua or Norma brass the flash holes are punched. Lapua and Norma drill theirs. Most other cases will have a burr inside the case around the flash hole. This needs to be de-burred once. As far as primer pocket uniforming, unless you are a BR shooter don't bother. I don't even clean primer pocket (other than making sure there isn't any media in the flash hole) because I didn't think it will gain me one more point in a match.
Trim all your cases to a uniform length. You only need to chamfer after you trim, this could be after 4-5 reloads. I weigh all my cases and batch them into 1 gr batches. This is more of a "feel good thing" I think, because the weight difference could be in the web of the case or the exctractor groove, or the .0002" wall thickness.
Like sunray said to get better consistancy, case volume is more important then case weight, but who has time for that if you are working with several hundred or a couple thousand cases at a time?