trim case length

[magnum]

i am new to reloading smaller cal as 204 picked up new rifle took it to set at 100 mts shot off about 40 rounds ( this is the bit i,m not sure about) took the fired cases to resize, cleaned, now set up to trim them to 1840,started trimming them not seeming to cut took them and checked aol lentgh and only 12 out fo 40 where over size is this the norm ? from 1846 to 1857 with these smaller cases ? loaded with h4895 from 26.5 to28 grains with a mix of 32and 40 vmax and 32 nosler heads its just with my 243 i have to trim all my cases any info ?? thanks IAN

[Rick in Oregon]

magnum: Many times new brass is under length right out of the bag. It's really not a big deal, but uneven length cases will also give uneven neck tension and affect LR accuracy, usually giving vertical stringing.

Couple of options: Trim all cases to the shortest length or trim them all the long ones to 1.840" and wait for the others to 'grow' to the same length. You could always sort them into two lots also. I'm guessing you're using Nosler cases.......they are usually under SAAMI trim length right out of the bag.

[magnum]

magnum: Many times new brass is under length right out of the bag. It's really not a big deal, but uneven length cases will also give uneven neck tension and affect LR accuracy, usually giving vertical stringing.

Couple of options: Trim all cases to the shortest length or trim them all the long ones to 1.840" and wait for the others to 'grow' to the same length. I'm guessing you're using Nosler cases.......they are usually under SAAMI trim length right out of the bag.

RICK i sized all csaes and checked that they where not over 1840 in length at the start before loading should have put that in my post it just i have never had this before

[Rick in Oregon]

magnum: Got it. I never trim new cases out of the bag, just chamfer and deburr the necks after neck sizing. Many, many times cases actually shorten when they are first fireformed, that's what's going on with your cases and exactly why I never trim new cases, just fire them the first time, THEN trim all to spec length.

Once the cases have been fireformed in your chamber and then trimmed to spec length, you'll find they all usually stay within about .002" of one another for a few firings until trimming is again needed to even them all up. HTH

[magnum]

thanks RICK will fire them off a few times and see how it goes

[Bill K]

By the way Rick. What do you trim your 20VT cases to? I have been trimming, seems to work in my rifle better, to 1.385. I believe the books show around 1.395 . I seem to have a very tight chamber. If I allow mine to creep upwards of 1.395 to 1.400 I start to enlarge the primer pockets, even tho I am under the pressure levels.. At least that is what I am finding.. So just curious to compare what others are finding.. Thank you to you and others, for info. BIll K

[Rick in Oregon]

Bill, I've been trimming my 20VT cases to 1.395" also. My Cooper chamber is 1.412", so I'd actually like longer cases, but they all end up within .002" +/- after fireforming, so I've standardized on that trim length.