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Consistency of OAL measurement

Posted: Sat May 23, 2015 1:03 pm
by RobB
Was measuring the OAL for both 155.5 and 185 Bergers last night in my new FTR riflle using a Hornady OAL gauge. How consistent do people get their measurements for OAL? As there is a lot to do with feel as you slide the bullet towards the lands I'm getting a fair spread of measurement. With the 155.5s I'm getting a spread of 20thou over 10 attempts (av 2.150"). Better with the 185's, max spread 13thou (2 thou if you ignore out the first one! - av 2.142" ignoring 1st measurement) after 4 measurements.

Just wondering how everyone else does?

Re: Consistency of OAL measurement

Posted: Sat May 23, 2015 2:05 pm
by JSC
Taking an average of several measurements is a good idea. The important thing is to find a method yourself which gives you consistent results and then only use the results with your reloading data i.e. don't compare your measurement with someone else who might do it by jamming the bullet into the rifle harder or softer.

One way I sometime do it is to gently slide the gauge/bullet into the chamber but not enough to engage the rifling and then tip the rifle slowly up to vertical (with the barrel pointing down) so that gravity is the only force acting on the bullet.

Bullet designs which use a tangent ogive (like the 155.5 Berger) will give you less consistent results because there's a less acute angle between the bearing surface and ogive, so it's more difficult to 'feel' when the bullet touches the lands of the rifling.

Re: Consistency of OAL measurement

Posted: Sat May 23, 2015 2:31 pm
by ovenpaa
The Hornady OAL gauge uses a plastic rod which is quite vague so you can look at replacing it with something a bit more solid, a suitable diameter knitting needle might be a worth a try.

Re: Consistency of OAL measurement

Posted: Sat May 23, 2015 5:16 pm
by DaveT
One of Ovenpaas equivalent tools is a better quality item but you should be able to get good consistency with the Hornady.

Try sandwiching the bullet between the Hornady pushrods at the breech end and a plastic or wooden dowel down the muzzle.

A gentle rocking action to get the bullet in and out of touching the lands should help you get consistent engagement just on the rifling.

Re: Consistency of OAL measurement

Posted: Sat May 23, 2015 7:07 pm
by RobB
mmmm wonder if I should add to my order ovenpaa is putting together for me for delivery next week

Re: Consistency of OAL measurement

Posted: Sat May 23, 2015 7:17 pm
by Alpha1
Ovenpaas is a much better product.

Re: Consistency of OAL measurement

Posted: Sun May 24, 2015 5:05 pm
by Dombo63
Alpha1 wrote:Ovenpaas is a much better product.
+1
Mine arrived the other week and the improvement in accuracy of my .308 hand loads was incredible.

Re: Consistency of OAL measurement

Posted: Sun May 24, 2015 11:05 pm
by Alpha1
Yes and built in the UK by British crafts men (man) what more could you ask for. :flag13:

Re: Consistency of OAL measurement

Posted: Mon May 25, 2015 4:49 pm
by Matt
Rob

I don't have any problems with mine and find that it reads pretty spot on, this was only achievable once I'd done a bit of smoothing out of the inner neck surface of the case so that no 'notchy' resistance was felt as you slide the bullet out, any slight resistance can make it feel like you're either at the lands when you're not or make you have to use uneven pressure on the rod which isn't going to help you with a consistent readings as you could be jamming the bullet by mistake!

Be carefully not to over do it as you don't want the bullet flopping around in the case!

David's version is excellent (as are all of his shiny things and gizmos goodjob ) and will last you forever if you fancy adding it to the workbench.

Re: Consistency of OAL measurement

Posted: Mon May 25, 2015 5:02 pm
by ovenpaa
Well given your league win this weekend something must be working reloading wise for you Matt!

lollol