Oal

[RemMag]

From what I've gathered around t'interweb, the OAL of a cartridge can be quite important to accuracy, as their is an optimum distance for the bullet to be from the start of the rifling.

How, then, do I ascertain how far it is to the start of the rifling in my particular rifle? Is it just a case of trial and error? :confused: Or is their a cunning little device I can get which will measure it for me so I can then produce loads of different OAL's knowing how far off the rifling each one will be?

I gather this issue is important, but I'm stumped as to the detail of it!:(

[russian sniper]

Stoney point do an oal gauge that you screw a specially modified case on to.
You then put your chosen bullet into the modified case.
Slip the gauge in to the chamber, then carefully push the inner rod through the case til the bullet touches the rifling lands.

Then you measure the modified case with the bullet fixed in it by the inner rod and that length is your max oal.

Which will then allow you to seat your bullets very close to the lands and find the "sweet spot" for that particular bullet.

HTH
ATB
Daz
:D

[stalker1]

here you go as russian sniper said

heres a link for the hornady web site

https://www.hornady.com/shop/?ps_session=e83187dece7a6eeada9826a0ee518d11&page=shop%2Fbrowse&category_id=fd215786476a600bb3a34eaef6e83165

[Grasshopper]

I have not done this so I do NOT know for sure, but would it not be possible to take a spent case, seat a bullet reasonably tightly into the SPENT case, load it into the camber, extract it very carefully and measure the OAL.

[Dave 101]

Dont forget your OAL may be dependent on bullet length and weight , and the depth of seating will affect your preasure , check with your load data manual . Dave

[Thewildething]

I have not done this so I do NOT know for sure, but would it not be possible to take a spent case, seat a bullet reasonably tightly into the SPENT case, load it into the camber, extract it very carefully and measure the OAL.

Take a fired case, re-size the neck, put 2 slits down the neck to the shoulder so a bullet seats in there fairly tightly. Push the bullet into the neck so its just held, chamber the round and eject it normally (carefully) and measure the OAL, do this a few times and get an average. Works for me.
Marcus

[stalker1]

Take a fired case, re-size the neck, put 2 slits down the neck to the shoulder so a bullet seats in there fairly tightly. Push the bullet into the neck so its just held, chamber the round and eject it normally (carefully) and measure the OAL, do this a few times and get an average. Works for me.
Marcus


but how can you be sure that the the bullet is at the correct OAL, mayber its enterd the rifleing and as you withdraw the bolt the bullet is pulled forward in the case or if the bullet is to tight it maybe that it will not move back when it connects with the rifleing there for it could be sat to far inwards,

no offence meant, but if a jobs worth doing it might as well be done right the first time, and for the price of the oal gauge is it really worth cutting corners and trying to do it on the cheap side ????

[mildot]

take a spent case, seat a bullet reasonably tightly into the SPENT case, load it into the camber, extract it very carefully and measure the OAL.



This is basicaly what i do. do this several times so that you get a same measurement 3 times then you know thats the max oal.

[25Pdr]

All I do is drop the chosen bullet down the barrel till it engages the rifling, carefully push a cleaning rod down the barrel till it touches the bullet, mark the rod, remove bullet close breech position rod against breech face and mark the rod again. The OAL of your round is the distance between the two marks.

BTW First post, just discovered Airgun BBS nice friendly site with lots of helpfull people.

[dicehorn]

but how can you be sure that the the bullet is at the correct OAL, mayber its enterd the rifleing and as you withdraw the bolt the bullet is pulled forward in the case or if the bullet is to tight it maybe that it will not move back when it connects with the rifleing there for it could be sat to far inwards,

no offence meant, but if a jobs worth doing it might as well be done right the first time, and for the price of the oal gauge is it really worth cutting corners and trying to do it on the cheap side ????

Yup that is the problem doing that way. With reloading, where we can, we must eliminate guess work. As described, the AOL gauge is a must.

However, It is not a good idea then to measure the length from headstamp to tip as bullet length can vary - put a magnifying glass on the lead tip of some bullets and look at the shape of them!! What you need to get is a Comparator together with the accompanying bushing for your chosen calibre. This device which attaches to your veneer gauge, measures the important ogive length of the bullet (the ogive of the bullet is simply the first bit of the bullet head that will touch the lands)

Peter

[littlefraggle]

You'll need to get a bullet comparator too which fits to your caliper as there is a significant variation within individual batches of the same bullet and with the comparator you measure the distance from the ogive to the base and therefore the bullet will always be the same distance from the lands although not always exactly the same OAL.

[Thewildething]

but how can you be sure that the the bullet is at the correct OAL, mayber its enterd the rifleing and as you withdraw the bolt the bullet is pulled forward in the case or if the bullet is to tight it maybe that it will not move back when it connects with the rifleing there for it could be sat to far inwards,

no offence meant, but if a jobs worth doing it might as well be done right the first time, and for the price of the oal gauge is it really worth cutting corners and trying to do it on the cheap side ????

My method compared to a OAL guage was 3 thousanths different:p

I dont know about you but 3 thou isn't the end of my world.

You are going to screw about with the OAL anyway to find the sweet spot so you dont need to know exactly.

Never had the problems which you speak of, every time I do it I get to within 1.5thou of the average (deviation of 3thou). Im not loosing any sleep;)

Marcus

[RURALRIMFIRE]

for what it's worth: there is a big difference in the OAL of the factory Winchester rounds and the factory Federal rounds which I use [100 grain psp in .243 win], yet it is very difficult to tell which round is which from looking at the target. They both shoot bl@@dy good groups!

[TikkaT3]

Get yourself an RCS Precision Mic. Money well spent for headspace measurement and seating depth. https://shop.rcbs.com/WebConnect/,DanaInfo=shop.rcbs.com+MainServlet?storeId=webcon nect&catalogId=webconnect&langId=en_US&screenlabel=index&action=CategoryDisplay&categoryId=C11J149&route=C11J149&tabNumber=0&beginIndex=0