Square necks

[260Ackley]

How important are square necks when reloading? I haven't had issues in the past with new brass, FL size to round the necks and load. I recently purchased some new 308 winchester brass and I'm use to some necks being out of round but most were pretty bad, and a vast majority were not square . I'm necking up to 358 so I'm losing some length already and would prefer to not trim but the necks aren't square. This isn't a bench or varmint gun, used for deer under 200yds. But I like my deer rifles to shoot no larger then 1 in groups at 100 yds. Do you think the squareness is an issue in this application?
If so I would loose more length and have to order in a new trimmer pilot.

[Oso Polaris]

Just to clarify - by "square neck" do you mean that the mouth of the cases are not perpendicular to the case body or that all edges of the mouth are not even/parallel with each other?

You want uniformity, which leads to consistent repeatability. I would recommend that you trim the case mouth so there is uniform contact with bullet as it exits case. If you aren't convinced that its worth the effort then load up 15 rounds (3 sets of 5 shots) without trimming and 15 shots with cases trimmed square to same length. Shoot them at range and Compare the results.

[260Ackley]

Case necks aren't perpendicular to the body. One side of the mouth is longer than the other

[260Ackley]

I've been reloading for years and have never seen cases this out of square so it hasn't been an issue. Super disappointed with the quality of Winchester brass.

[Bill K]

I would trim/square the off as little as I had too and then measure to see if they are way to short to use. Or call the company and see if they would replace them. Bill K

[TinMan]

I would trim to square them up.