Coa with 80 gr SMK measurement
- Thread starter ripley
- Start date
dstoenner
Silver $$ Contributor
Make sure the chamber is clean. I have seen carbon and stuff mess up my readings. I also scrub my throat with JB bore paste before I measure. I only push till the first resistance. That will usually leave the bullet lodged gently in the rifling. After a while you get a feel for it
David
David
Ned Ludd
Silver $$ Contributor
It takes very little force to push a bullet into the lands well past "touching". If you're jamming hard on the rod but only intending to measure the distance to "touching" the lands, which is what the Stoney Point OAL gauge was designed to do best, you're wasting your time. You can certainly use that approach to find the distance to a hard "jam", but that's a measurement I personally find to be less than useful.
To reproducibly measure the distance to "touching" with the Stoney Point tool is not difficult, but it requires practice to develop a feel for the first very light contact of the bullet with the lands. My suggestion is to practice using a single bullet over and over again until you can reproducibly obtain the same measurement with it. If you cannot obtain consistent measurements with a single bullet, the odds are not good that you will be able to do so with multiple different bullets. Make sure everything is as consistent as you can make it, i.e. the pressure with which you push the outer rod/case into the chamber, the clock position of the inserted rod/case as viewed looking straight down the barrel, the light push you apply to the center plastic rod/bullet until the "touch" is felt. All of these things need to be consistent to obtain consistent measurements, and practice is how you get there.
To reproducibly measure the distance to "touching" with the Stoney Point tool is not difficult, but it requires practice to develop a feel for the first very light contact of the bullet with the lands. My suggestion is to practice using a single bullet over and over again until you can reproducibly obtain the same measurement with it. If you cannot obtain consistent measurements with a single bullet, the odds are not good that you will be able to do so with multiple different bullets. Make sure everything is as consistent as you can make it, i.e. the pressure with which you push the outer rod/case into the chamber, the clock position of the inserted rod/case as viewed looking straight down the barrel, the light push you apply to the center plastic rod/bullet until the "touch" is felt. All of these things need to be consistent to obtain consistent measurements, and practice is how you get there.
memilanuk
Gold $$ Contributor
When I use the Stoney Point tool, I use the straight (in-line) tool, not the angled (cable) version. And I go for a hard jam. Stick it in til it stops, and tighten the brass set screw. Use a cleaning rod or drop rod to tap the bullet back out, put it in the modified case and take your measurement. It does help to practice it until you get consistent readings with one, after which I may (if I'm being perticuler) take a series of measurements (3 reads each on 3 separate bullets) and then go off the average.
Nowadays I prefer to use the Wheeler method with my bolt guns, but I haven't found a good/easy way to make that work with an AR.
A side note for those who poo-poo the 'hard jam' approach with the SP tool: when people started using the Wheeler method more a few years back, there was of course some comparison with the previous reads taken with the Stoney Point / Hornady type COAL tools. Most people found they were off a considerable amount - 10 to 20+ thou off. For me, with a 'hard jam' approach, my reads with the SP tool were within a thou or two of what I get with the Wheeler method. To each their own
Nowadays I prefer to use the Wheeler method with my bolt guns, but I haven't found a good/easy way to make that work with an AR.
A side note for those who poo-poo the 'hard jam' approach with the SP tool: when people started using the Wheeler method more a few years back, there was of course some comparison with the previous reads taken with the Stoney Point / Hornady type COAL tools. Most people found they were off a considerable amount - 10 to 20+ thou off. For me, with a 'hard jam' approach, my reads with the SP tool were within a thou or two of what I get with the Wheeler method. To each their own
Upgrades & Donations
This Forum's expenses are primarily paid by member contributions. You can upgrade your Forum membership in seconds. Gold and Silver members get unlimited FREE classifieds for one year. Gold members can upload custom avatars.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.
Click Upgrade Membership Button ABOVE to get Gold or Silver Status.
You can also donate any amount, large or small, with the button below. Include your Forum Name in the PayPal Notes field.
To DONATE by CHECK, or make a recurring donation, CLICK HERE to learn how.