.458 WM, Huh???

[hoytcanon]

Howdy AH Reloading folk,

I have been reloading for decades and for .458 WM for most of that time for many rifles. I have a standard load of 75.0 H335 with 500 RN's @ 3.340" that works perfectly in my current Carbine. I am in the process of developing a somewhat reduced load, for the spring bear season, utilizing the Barnes original .458 400 grain SP using H4895. With a target speed of 2000 fps, I calculated approximately 64 grains and loaded to 3.300". My first test load was cycled in the rifle, but upon ejection the bullet stayed in the leade and the cartridge ejected, dumping the powder in the action. I thought that maybe I screwed up the OAL, so I remeasured three rounds, and after punching out the stuck bullet, attempted to cycle a round from the magazine... same thing happened. I then punched the bullet, removed the rounds in the mag and reduced the OAL to 3.250"... same thing happened again... jammed bullet, dumped powder... I pushed the bullet, cleaned the action reduced another round to 3.200" and tried again, this time it fed and cycled properly and smoothly.

Here is my question, maybe someone has the answer? If the 500 RN at 3.340" feeds and ejects perfectly, how is it that the 400 SP has to be reduced to 3.200" in order to feed and eject??? See picture below. Any and all comments welcome.

 

[baxterb]

At what point are the bullets the exact same diameter? I had an issue with Swift 300gr bullets in my 9.3 - they would get stuck. I took each of the bullets i was testing for feeding, stuck them in the muzzle and drew a line. here are the results from L-R:
Barnes 250 TSX, Swift 300, North Fork 286, Woodleigh 286, Woodleigh 250, North Fork 286 (Cup Point), Barnes 286.

It solved that mystery real quick.

 

[John Wasmuth]

Shorter fatter bullet requires deeper seating.

 

[John Wasmuth]

Make some dummy rounds using both projectiles. Coat them with a sharpie from crimp forward and then chamber each, you’ll find your answer. O Gives are different.

 

[hoytcanon]

Make some dummy rounds using both projectiles. Coat them with a sharpie from crimp forward and then chamber each, you’ll find your answer. O Gives are different.

I just realized what I did when I compared the ogives as being the same... I compared the 500 RN to the 400 SP "AFTER" I had shortened them to 3.200" not to the 400 SP at 3.300"... when I did that the problem was apparent. Age and haste create many problems for reloaders! Lol

 

[hoytcanon]

Seating these deep is not an issue as I am using a reduced load anyway, 3500 ft/lb is plenty. These should be terrific on bears. Zeroed 1" high @ 100 yards, I can hold dead on from 0 - 150 yards and never be more than 1.6" from POA.

 

[IvW]

You nee to measure the jump to the lands and load accordingly. On my dg rifles I prefer a big enough jump. It is not a target rifle.

 

[BryceM]

Each bullet has a different ogive profile, and therefore will contact the lands at a different OAL.

 

[Tex .416]

You need to measure base to ogive.

Use the correct diameter insert and lock onto calipers. Very easy to use and helpful when swapping bullets as you are doing.

Hornady Lock-N-Load Bullet Comparator Basic Set 7 Inserts

The Hornady Lock-N-Load Bullet Comparator is perfect for the reloader looking to quickly and precisely measure seating depth of loaded ammunition from...

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