I just started reloading for my .223. The Winchester brass that I bought is shorter than the trim-to length (its 1.748 vs 1.750"). Will this cause any problems? If I dont trim the brass the length will vary slightly from round to round. I would think that this will cause some variation in accuracy. Should I trim all the brass short so it's uniform, or shoot it a few times and see if it grows?

I checked some fired cases from the factory Winchester ammo that I shoot and they are also a little short, is this common?

Elkhntr

.002 isn't too bad, some bags of cases do run a little short. If they were mine, I would trim all to the same length and load as usual. Did you resize them, sometimes you get a little growth with sizing. Unless you have a very short chamber,they will generally lengthen after a couple of firings.

Always go for consistency.I mainly shoot an AR15 with a Wylde chamber (not especially tight) and have not noticed a problem with short cases, but have tested with mixed length cases and have noticed a slight increase in group size with mixed cases.

good luck

Covey16

Unless you are crimping the brass for auto use I would just load the brass and then trim it to the trim length when it grows......I haven't seen this in 8 different brands/batchs of 223 but only one is a new purchase.....I got the chamber length gauges from Sinclair and it will suprise you how long some chambers are compared to "book" trim length and it hasn't hurt those guns/chambers.......good luck and good shooting-loading!!

elkhntr
The thinking on consistent case length is that you get the same bullet pull on all rounds.
.002 isn't much , it just depends on what level of accuracy you are looking for.
Like bigdaddyacp said, it important when crimping. I personally don't crimp rifle cartridges, but some do.
Happy Holidays
Covey16

Thank you for your posts. I think I'll re-size the brass and then pull the worst cases out (anything over .002 difference). It looks like i'll remove about 10%. I'll use them for plinking and keep the rest for target shooting.

elkhntr, hold onto your britches now...here's one to think about!!!

I load for six .223 rifles. 2 Remingtons, 2 Sakos, 1 Interarms mini and 1 M-70.

I hate to trim brass...it's a pain is the ars!!! So when I buy a batch of new brass I trim them all back to .03 under the 1.76...yes...I trim them to 1.730!!! That way I never have to trim them again. When they reach 1.76 I scrap them and get new ones.

I've fired thousands of rounds this way with no ill effects at all and accuracy has never been a problem with any of them.

Thats something to consider. I hate to trim brass as well. I just want them to be uniform. If it wont affect the way it shoots I may have to try trimming them all.

Full length resize before measuring or trimming any brass.