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> 7x57 seating depth
7x57 seating depth
@ 01:45 am (GMT) |
bill moralesi have an 1895 chileno Mauser with a really deep throat.Even if I seat bullets so they barely fit the magazine, they are still .085" off the lands (Barnes 175gr. Tsx). The magazine will fit cartridge lengths up to 3.1", which is a good 1/8" longer than COALs specified in many load books I've read. I know that loading to longer lengths reduces pressure, and that loading closer to the lands yields better accuracy. So, I'd like to add a little more powder to compensate for the lower pressure while seating closer to the lands, but also keep velocity up to levels similar to the specified COAL. I'm not looking to hotrod it up past safe pressures for a small ring mauser I do not have access to a chronometer. My question is, how do I figure out how much more powder can I add without blowing it up or spending a fortune creeping up on a happy medium? The gun is in great condition with less than 200 rounds thru it since the '60s, and I don't think it's a ragged out old relic - but I'd hate to wind up with the bolt sticking out of my face.... Any ideas? |
Replies
@ 02:47 am (GMT) |
chris murphyRe: 7x57 seating depthHi BillThere is a lot of info on the 7x57 in the knowlage base you may find the 175grn slow killers due to lack of speed. As far as seating depth make sure the body of the bullet fills the whole neck of the case to achieve max concentricity. I set up an old m77 ruger in 7x57 with 139 sst they were jumping about 2mm |
@ 03:12 am (GMT) |
Ben GradyRe: 7x57 seating depthQuote: Hi Bill
There is a lot of info on the 7x57 in the knowlage base you may find the 175grn slow killers due to lack of speed. As far as seating depth make sure the body of the bullet fills the whole neck of the case to achieve max concentricity. I set up an old m77 ruger in 7x57 with 139 sst they were jumping about 2mm Hi Chris, I know this off topic but is... "the bullet fills the whole neck of the case to achieve max concentricity" more important than trying to seat the bullet just off the lands and further forward in the neck. I have been reloading for a few years now, but still a novice really. So I have been seating bullets 1mm off the lands, which is probably forward in the neck but I try to stick to about 1 x bullets diameter left in the neck. Am I better to seat deeper so the bullet fills the whole neck? Which? is more important for accuracy and to get max fps. cheers Ben |
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@ 03:30 am (GMT) |
chris murphyRe: 7x57 seating depthHi Ben by bullet body filling hole neck I mean make sure the base or start of the boat tail is at least at the bottom of neck/top of shoulder (see the pic on home page of 308 and amax with callipers) if your throat allows then seat out to lands. With more jump you can sometimes get more speed. You may have to play with loads and seating depth to find sweet spot. The m77 I did shot .5" with boat tail base at bottom of neck (139sst) this was before I knew about bedding and Nathan's knowledge. I'd love to have another play with it knowing what I know now. |
@ 01:14 am (GMT) |
thomas kitchenRe: 7x57 seating depthhi billim new to this reloading game still got alot to learn ( starting to see how its addictive) and really looking forwards to nathans reloading book. when i talked to nathan bout reloading his advice was to load bottom of bullet inline with bottom of neck like chris has said. i ended up making a dummy round 1mm shorter then magazine which is slightly setted below bottom of neck from memory and checking it would cycle fine then done a ladder test from there. |
@ 04:35 pm (GMT) |
Nathan FosterRe: 7x57 seating depthThanks guys, been so busy with the book edit.I hope the guys advice helps you Bill. |
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@ 04:40 pm (GMT) |
Nathan FosterRe: 7x57 seating depthSorry- one more thing, the closer you get to the lands, the higher the pressure (immediate resistance at the lands). The deeper you seat, the lower the pressure due to energy being used to get the bullet to the lands.You will have less dramatic pressure spikes if you seat deep, a more linear relationship with no hidden surprises when working up optimum power loads. |
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