Ogive head space ???

[Gerry939]

I reload I am getting good results, but I'm told I could do better if I work out the distance my bullet is jumping to the lands, is this Really going to help and if so what do you use...head space gauge. Do you measure your oal from the ogive ?..or the tip of the head. My oal is identical and my rounds fit in the mag. If I increase the oal I would have to shoot one at a time ...is it better...or more accurate

[Rockhopper]

Coat the bullet with felt pen, chamber the round (with no powder in the case!!), see if there are rifling marks on the bullet. If non then pull it out a touch and repeat till you see marks then go back a couple of thou.
Sadly that doesn't work on my Parker Hale T4 as the chamber is so massive the bullet falls out of the case before it touches the rifling!

[WelshShooter]

Typically, reloaded rounds are measured for overall length by using the case head and the tip of the bullet as the datum points - and this is the measurement provided in reloading manuals. You can also measure a loaded round from the case-head to the ogive of the bullet, but you will need a calibre specific gage to do this. The amount of bullet jump is defined as the distance between the ogive and the start of the rifling. Base to ogive is a good measurement that does not change between bullets. For example, Lapua Scenar bullets of the same mass as Sierra match kings will have different overall lengths but can have the same base to ogive length. So if you know that you rifle shoots well with a jump of 0.003" then at least you know where to start when you try a different brand of bullets.

You can measure the distance to the rifling in two ways:
1.) Produce a range of dummy rounds (i.e. no powder or primer) whereby the base to ogive is increase incremently. Remove the spring from your bolt and load each round in and close the bolt. You will eventually feel a small amount of pressure when you try to close the bolt and you should see some markings on the bullet. This indicates the start of the rifling. Take note of the base to ogive measurement.
2.) You could use an overall length gage system to quickly work this out.

I have performed step 1 a couple of times and although it is slightly time consuming, it works well enough for my needs. I have measured all my base to ogive measurements using a Shooting shed gage (get in touch with Ovenpaa or Christel on this forum) as they are very accurate and British made so I would highly recommend them.

Bear in mind that certain rifles, for example, Lee Enfield's, have generous throats and you won't be able to touch the rifling with a loaded bullet!

[Blackstuff]

You can do it the cheap slow way or splash the cash on something like the Hornady system;

http://www.cdsgltd.co.uk/hornady-comparatorbody.html

http://www.cdsgltd.co.uk/hornady-oalgauge-curved.html

http://www.cdsgltd.co.uk/hornady-comparator-insert.html

http://www.cdsgltd.co.uk/hornady-modified-case.html

£80ish from CDSG for a single set up and then £13 for the stuff you need per extra calibre

[Gerry939]

Thanks blackstuff for the links, which comparator insert is 6.5 creedmoor, the bullet is actual .264 or .256 imperial? ?
Thanks

[Blackstuff]

I would GUESS its the 0.257 one as 6.5mm = 0.256" but I'd ring the shop and ask to be sure

N.B. There is also the straight OAL gauge;

http://www.cdsgltd.co.uk/hornady-oalgauge.html

But its £20 more expensive and can't be used on some types of guns

[Alpha1]

The shooting sheds are much better quality and a lot easier to use.
http://shootingshed.co.uk/oscom/index.php?cPath=38

[Tomo]

I used the Hornady comparator set to measure the distance to lands in my 6.5mm RPR last week (it's the .264 gauge, code 5-26). I bought just the gauge body and the inserts I needed instead of the whole set to save a bit of cash (got them from McAvoy's)

Plenty of instructional videos on YouTube too; here's one of the better ones.

https://m.youtube.com/watch?v=3kL0HIgqq ... e=youtu.be

[Gerry939]

Thanks Tomo
Pointed me in the right direction
Thanks to all...again..