case length question

toad67

bought Hornady 160 grain Leverolution FTX bullets.I have on hand Winchester 748 powder.

Hornady suggests trimming cases shorter than the normal .010" under max SAAMI length.

Anybody know how much shorter than the normal 2.029 the case should be trimmed to?

Thanks in advance for any information.


Loading FTXT bullets requires some specialized techniques in certain
cases. To achieve a high ballistic coefficient we had to lengthen the
ogive, or nose, of the bullet. Sometimes this requires that the cartridge
case to be trimmed shorter than the suggested .010" under SAAMI Max
length that we recommend for conventional bullets. Follow prescribed
trim lengths exactly as presented in the FTXT data for optimum results.


MAX. CASE LENGTH: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; 2.039"
CASE TRIM LENGTH: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; 2.029"BULLET DIAMETER: . . #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; .308"
RIFLE: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; WINCHESTER M-94
BARREL: #65533;#65533;#65533;#65533;#65533;#65533; 20", 1 IN 10" TWIST
CASE: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; REMINGTON
PRIMER: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; FEDERAL 210
BULLET: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; 160 GR. FTX
MAXIMUM C.O.L.: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; 2.550"
SECTIONAL DENSITY: #65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533;#65533; .241
BALLISTIC COEFFICIENT: #65533;#65533;#65533;#65533;#65533;#65533;#65533; .330

http://www.hornady.com/assets/files/...30_win_ftx.pdf

toad67

Getting to reload some 270's for deer hunting. I opened a new sack of winchester brass. I have resized them and ran the RCBS hand deburring tool thru them so that they are ready to go. Before I deburred them I checked my new Nosler book and an older Barnes book that I had for max case length. Both books said that the max length should be 2.540". All of the brass was betweem 2.530" and 2.540", nothing over the max length. I am going to reload some Barnes TSX bullets and my new reloading book should be here tomorrow but i decided to do a little online looking at their website. Barnes says that case length should be 2.530". Should I trim all of my cases .005-.008" or should they be okay to load. I am switching from original X bullets to the TSX's and will have to work up a load with these. Thanks in advance.

todd

Rocky Raab

The max length is 2.540" and the trim to length is 2.530".

If you aren't going to crimp your loads (and you probably should not), you can go ahead and load all of them as-is. You'll almost certainly have to trim them after you fired and resize them. When you do, trim them to 2.530".

toad67

Thanks for the info Rocky! So is it safe to assume that all is okay if all cases are between the trim and max length? How much is accuracy affected if cases are varied in length between the 2 lengths during load work up?

Todd

Okie743

IMHO:
You only need to be concerned about the hull length vs accuracy if the hull length exceeds the max length limit or is at the max length l;imit and could exceed max length when fired. If too long the brass will be saueezed into the rifling and have an effect on the bullet pull from the hull and pressures!

Sometimes NEW brass when first fired will stretch from the min to the max length, therefore I sometimes trim New or once fired brass little shorter by approx .005 (2.525 in your case) so as I don't have to be constantly trimming the hulls.

Keep a heads up and if you have to trim from max three times on a brass hull the brass is getting thin usually. Neck sizing only reduces the brass working fatigue and increases case life usually, but neck sizing of brass should only be done on bolt action type rifles.
I also use different color marks a lot felt tip pens and color code the headstamp end my hulls as to the number of times they have been neck sized and reloaded. like for example, no color = new brass, Black=1st reload (this is 2nd times fired from when new) Red=2nd time reloaded, green=3, etc. I also keep note of how many times a hull has been trimmed which is most important to help eliminate case separation failures! If neck sized only for a hunting rifle, I also chamber test the neck sized ammo before placing in a container for hunting purposes.

I also pay attention to how much the brass is stretching in a rifle and if brass is constantly stretching to near max limits, the headspace is suspect or the amount of powder load should be reduced.[;)]

sandwarrior

taod67,

As of right now, while it's fresh in your memory, trim them ALL to 2.530". No sense in going into shooting for accuracy leaving them all different lengths. Case length is an accuracy factor. Don't leave it differrent with all of your cases.

oneoldsap

I'd agree with sandwarrior , trim them all to equal length before doing anything else with them . I mark on my load labels how many times loaded and trimed . like 3T1 means loaded 3 times trimed once ! I never trim brass more than 3 times before scrapping it .

Rocky Raab

toad, I'll assume you aren't a match shooter or you'd already know the answers to the questions you asked.

For "sporter" accuracy with a factory rifle, you probably can't tell the difference between trimmed and untrimmed bass - especially on the first firing. After that, you might, but the main difference will be cases that stretch enough to either pinch the mouth against the bullet when chambered, or not allow the round to chamber at all. Both are bad.

Load 'em as is. Shoot them. Trim to a uniform minimum length after resizing. Check them after every subsequent sizing and trim as needed. Loads under maximum will cause less stretching, and using an inside neck lube will help minimize it. If you have to trim often, case life will be short. Three to five trims are all that most sensible guys allow.

Okie743

Rocky: Well said!

I was also just indicating a sporter rifle.

toad: maximum accuracy when reloading is consistency, (doing all the same) from the shooter to the reloading of the brass.
You may want to eventually even start match weighing your brass
and it's not uncommon to find NEW brass that some hulls is max length and needs trimmed before reloading.

Warning, reloading and max accuracy can get to be a GOOD never ending thing and a continual learning process!
Welcome aboard!

Navybat

Many have said this, and I'll reiterate, not that I'm an expert, but because it's important:

trim AFTER resizing! This is a simple, even obvious step, but I've heard many buddies tell me they forgot this, then resized and had to trim again!