continuing saga of the 280 rem
so after getting my powder situation straightened out i started to reload for the new to me 280. loaded a case using a sierra gameking 150 gr. my manuals state min cart length of 3.330 to 3.30. loaded a round at 3.30. had a hard time closing the bolt. ejected the round and could tell the bullet was engaging the rifling. checked some rem. 165 gr factory rounds and found they measured anywhere from 2.52 to 2.65. started adjusting bullet seating depth and testing in the rifle. found i had to be at 2.65 for the bullet to just touch the rifling. am i doing the right thing here? if so why do the books state that min col is 3.330. i load for a lot of different calibers and have never had a col problem.
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I usually consult 2 or 3 books for a new round to me. Especially useful when it was a 280, then a 7mm Express then back to the 280.
I generally set the ogive about .003 out of the rifling. With a heavy coat of candle soot on the bullet the cartridge is chambered/extracted. No marks from the riflings is good. Sharpie black is really thin, so no marks - then seat the bullet deeper. Measure the thread pitch on your seating stem; calculate what % of a turn is .003 or so. Don't load a lot until you shoot a few checking for signs of pressure and group size.
I seat the bullet 1/2 way, lower the ram - spin the case 180 degrees then finish seating the bullet.
Bullet profile can be vary different, that's why they specify the bullet in better data. All 165 grain bullets are not the same.0 -
Case length is 2.54"
A loaded round at 2.65" would look pretty funny.
What are you really measuring?0 -
sorry i lost connection between my fingers, eyes, and brain. 3.265 is actual measurement. 0 -
Factories are not real careful about throats length.
Handloading lets you fit the ammo to the gun.
I would not load to the lands for a hunting rifle.0 -
Reloading manuals give COAL as set by standard dimensions. The chambers of assorted rifles will often differ from standard dimensions for various reasons.
Part of the reloading process is using personal observations and adjusting certain things according to what you see with your specific firearm.0 -
Once you determine what jump you or your rifle desires and you want to test a different style, weight bullet type you might consider getting one of these 6 sided bullet comparators.
Not expensive and I use one of them quite a bit.
Your 280 will use the 7MM hole.
Here is a you tube link explaining general procedure.
https://www.youtube.com/watch?v=u6P3GeLn2BA
Get's your reading from the Ogive of the bullet instead of over all length and once you have your desired ogive you will use the same reading for each type different of bullets for that one GUN. Sinclair also makes a tool to get the zero jump of a gun without a bunch of trial and error.
If you are darkening the bullets and chambering to find the zero jump, use a propane cigarette lighter and hold the bullet at the very tip of the flame and play/roll the bullet in a dummy case with the bullet a snug slip fit and then later use a marks a lot pen and color the bullet.
Sinclair, Hornady plus others make the oal zero jump tools and saves a lot of farting around trial and error testing if you are going to be doing more than one gun.0 -
quote:Originally posted by Hawk Carse
Factories are not real careful about throats length.
Handloading lets you fit the ammo to the gun.
I would not load to the lands for a hunting rifle.
Good tip. zero jump is asking for a problem with a hunting rifle (might leave a unfired bullet stuck in the bore in big bear country) and you will find that jump is not too critical for a hunting rifle's accuracy when you are looking to reduce a 1 1/2 inch group size by say 1/4 inch AVERAGE. If the gun is shooting a 1/4 inch group you might reduce the guns group too a one holer by playing around with jump, if you are up to the task yourself.
Some Weatherby's hunting rifles the jump (leade) is so much that the bullet cannot be set out enough for zero jump.
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