Idiot reloading mistake No. 1

[User702]

Just did a bit of quick checking in the cave over lunch. It looks like 3/4 of a turn past zero (for want of a better word) on the collet die produces a goldilocks level of neck tension, so I will be using that for the remaining bits of brass. I ran out of time to check the full length die and whether I can take the decap pin out, but that's on the list for tonight.

If I can't make that work for me, then I may have to make a trip west to the Bedford badlands to Chez Ovenpaa.

Apparently a new mandrel will cost me a fiver, so not too bad and maybe a worthwhile investment for the future.

[dromia]

The decap pin, expander ball abomination, assembly comes out on all current makes of dies.

What make are yours?

I'm assuming Lee if you have a collet die, if so a couple of suitably sized spanners is all you need. You could also take the opportunity whilst you have the rod out of replacing it with a plain universal decap pin rod and bin the expander ball sh!te.

[ovenpaa]

I tend to just drop the mandrel out and machine the expander ball down and they are good to go, it is a 5 minute job and with a bit more imagination they make wonderful universal decappers just by backing the die back/extending the shaft down.

Head over this way and we can spend a couple of hours going over the reloading basics and maybe even persuade the Viking to throw some powder in the cases.

[Dougan]

That's when I noticed that they slipped straight into the neck of the case.

That's when I also realised that I'd cocked up quite badly.

Did the same thing myself last year...don't forget to get an 'inertial hammer' for future cock-ups

[User702]

Last night saw me back in the cave (after my daily three mile run) properly neck sizing my remaining brass and then swapping to the full length sizing die to tighten up the necks of the ones I cocked up. They now have enough tension to hold a bullet, so things are looking up.

On impulse I also made an OAL thing with one of the 2156s and a case. The exact measurements are to follow (they are in my notebook), but it would appear that my rifle's overall cartridge length is over 2.95 inches, which struck me as quite long given the OAL length of a complete round according to SAAMI and wikipedia is supposed to be 2.8"

[Christel]

If that is a Remington they are mostly like that, Sir.

[rox]

On impulse I also made an OAL thing with one of the 2156s and a case. The exact measurements are to follow (they are in my notebook), but it would appear that my rifle's overall cartridge length is over 2.95 inches, which struck me as quite long given the OAL length of a complete round according to SAAMI and wikipedia is supposed to be 2.8"

This photo is titled "Long range VLD Projectiles and standard OAL's do not go together", and shows what a VLD would look like if loaded to 'standard' 2.8" OAL**. The 2156 is not quite what you would call a VLD, but it is somewhere in between a 'standard' bullet and a VLD, and is considerably longer than a 2155 (but the base to ogive length is pretty similar). Depending on your chamber you may find that your preferred small jump or jam doesn't leave enough of the bullet in the neck - a general rule of thumb is that at least one calibre depth of the bullet's bearing surface (the full-diameter portion) should be held in the neck. The 2156 doesn't *need* to be jammed or short-jumped to work well though, so don't worry if this constraint in your chamber leaves you jumping 0.040" or more.

** The 2.8" OAL standard for .308 Winchester ensures that rounds will feed from a magazine, and establishes a frame of reference for load data that can be reproduced with basic tools (calipers or simple gauges only) while ensuring that the loaded round case-volume isn't wildly different from the test data. It is not particularly relevant for loading precision ammo or using the more specialised target bullets, and measurements to the bullet tip/meplat are not as consistent as measuring to the ogive (since there is often relatively significant variation towards the thinest part of the bullet). On the other hand, measuring to the ogive is critically dependant on the comparator tool used, and is therefore not really suitable for reference data that will be shared with others who will be using different comparators.




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[User702]

Interesting info Rox, I will digest that later.

When I popped in to see Ovenpaa and Christel at the weekend he broke out Quickload and suggested a couple of likely starting points for a load based on a cartridge OAL of 2.85". Given the differences between even that and the measured OAL (90 thou if my old skool maths is up to speed) I'm tempted to increase the OAL a bit (keeping the above advice in mind of course)

Comments?

[IainWR]

The measurement that matters, as Rox indicated, is the base-to-ogive length. Now the 2.800" OAL works for milspec 7.62x51, but match bullets tend to be longer (all else being equal, longer = less drag). If you load a Sierra 2155 to 2.800" OAL, then load a 2156 to the same base-to-ogive length, the result will have an OAL around 2.920". Equally, if you do a chamber length measurement with a 2156 you will get an answer about 0.12" longer than if you measure the same chamber with a 2155. The result will vary quite a bit depending on the individual bullet - as Rox said a measurement on a curved slope is subject to a lot of variation and the words "around" and "about" are significant.

[User702]

Taking onboard Rox & IanWR's comments above, I broke out the micrometer and did a bit of measuring...

Cartridge OAL is 2.963" with a 2156 bullet installed.

However, this does mean that only about 0.09" of ogive is actually in the throat of the case, so to maintain about 0.3" of that in the throat of the case (as suggested by Rox) I would have to seat the bullet low enough that the cartridge OAL would drop to about 2.76". The middle ground (using the 2.85" OAL suggested by Ovenpaa and Quickload) would give me a decent amount of ogive in the throat (about 0.2") whilst at the same time providing a touch more space for the TR140.

This stuff hurts my head. Maybe I'll just give it up and buy milsurp instead...