Poor mans bullet seating test??

[woodspider]

Ok after giving up on my RCBS fake bullet precision mic to find ogive, oal, coal.
I attempted the following and repeated over and over .
I took a piece of Lapua Brass and a.308 SMK 175, adjusted the neck tension so that it held the bullet (way long) but allowed movement into the case when slight pressure applied. Placed it into action by hand but not too far then slowly closed bolt, then retracted bolt slowly removing round and measured getting 2.890, did this over and over,and over getting 2.890 consistently. (And yes I pre-measured it was pushing the bullet into the case to 2.890 and no more than that, that wasnt where I set it at to start.)
Ok Question what am I looking at meaning this 2.890 measurement??? my OAL my COAL, ogive is what then? Is this where my lands begin contact or am I just wasting time with this method? Any advice appreciated,

 

[jrob300]

Re: Poor mans bullet seating test??

By doing what you've done, you've found the lands (or *just* into them). Now, you need a way of accurately repeating that measurement, as bullets are not always the same length to the meplat. You need to know where the ogive is. So buy one of these:

http://www.midwayusa.com/viewproduct/?productnumber=231904

Measure the round you worked up with the gauge and your caliper and you will have a number that you can duplicate for your loaded ammo. If you want to run .010 off, just subtract .010, etc.

John

 

[Fuzzball]

Re: Poor mans bullet seating test??

Yes, you've found where the bullet ogive contacts the lands and that's all that matters. (No rifle cares where the point hangs in space so OAL, as such, means nothing for accuracy.)

Most factory made rifles and common bullets do best with a jump to the lands from .020" to five times as much so striving to find the lands to 1 thou is an exercise in futility without value; get close and use that as a reference for your load development tests.

Your RCBS Precision Mic's seating thimble will allow you to repeat any seating depth you wish, and with great accuracy, so the Hornady tool would have no value for you. And the Mic's case shoulder thimble will let you set your sizer exactly as you need it to be too.

 

[manshooter]

Re: Poor mans bullet seating test??

I agree with fuzzball for the most part. However I do have two rifles that I punch paper with on a regular basis that are picky about how much jump they have to the lands. I set one of them at 10 thousands and the other to 17.
Not a LOT of diff, that's true. But for paper punching when every thousands count it does matter. For hunting it is not important at all, as long as the gun will group well for that purpose.
I Check mine the same way you do, and I have been doing so with great results for over 30+ years. I just check each bullet I will be shooting to find what the OAL is when seated and make a dummy round to adjust the seating die with if I switch bullets for paper or fur. I just give them an extra firm crimp when so I can make sure the seating die can hit them solid without pushing the bullet in any further, and having to re-adjust all over again. It saves me time in the long run as I load for many different calibers and I use this method for all of them.
Good luck with your task.

 

[9H_Cracka]

Re: Poor mans bullet seating test??

Coat the bullet with Dycum or magic marker so you can see where it engages the rifling and how much engagement there is - you can actually measure it with dial calipers.

You can slot a case neck with a hacksaw as well and play with tension easier with this.

A gunsmith/multiple HM card holding shooter friend of mine said the following are his instructions on how to use a Stoney Point:

- take it apart into as many pieces as you can
- put each piece in a different trash can
- hope no-one finds the pieces and puts it back together

He's a proponent of the bullet in case method, needless to say.

 

[Greg Langelius *]

Re: Poor mans bullet seating test??

While I agree that knowing and managing the ogive-to-lands relationship can yield accuracy gains, and I used to worship at that and several other altars of excellence; I made a conscious decision to back my enthusiasm off a notch and concentrate on simpler methods that still yield reliable, albeit less totally precise, results.

I asked myself whether my interests lay in the peerless precision of ammunition making, or in getting to the range and working on my marksmanship. No arguments, they are both necessary.

My answer was that for me, handloading is a necessary evil that one must undertake in order to be able to afford to shoot more frequently.

So, I asked myself further, just what was it that I could and could not divorce myself from, and just what was the real bottom line regarding handloading and accuracy.

Money and time are my key issues. Never enough of either.

For jump/no jump, my conclusion was that for me, it mattered somewhat less how much than whether it did or didn't reliably.

Therefore, I measured ogive contacting OAL for a discrete number of bullets in a batch, found the shortest OAL, and deducted .010" from that. This provides a reliable 'they all jump' seating length.

If I wanted to, I could progressively load to that length, and it would make very little difference. I don't load (not completely anyway) progressively, but seating length is something I simply perform, and don't check beyond occasionally spot verifying that it hasn't changed.

Surprisingly, it seems to have had very little impact on accuracy.

My bugaboo is neck tension, and I have my own method of simply and reliably managing that, despite neck work hardening.

Greg