On top of lands , minimum bore diameter . You want about .003 " larger bullet/sabot size , give or take a thou .. Bore is easiest to measure using a " small hole guage" then measure it with a micrometer . Starret and others make those guages .How do you measure the bore?
Is it top of the lands (min bore diameter) or bottom of grooves (max bore diameter)?
New thousand of Win 209 (blue box), I got around to measuring some and was surprised to find they are shorter than previous. The new primers measure. .296 to .300 in length. May be a good thing .
New thousand of Win 209 (blue box), I got around to measuring some and was surprised to find they are shorter than previous. The new primers measure. .296 to .300 in length. May be a good thing .
When i had my Knight Mountaineer i ran across this same thing with my Win 209 (Blue box) i ended up measuring and sorting all of my Primers, I couldn’t use The Longest ones (The longest ones I found were .301) They would Get “Sticky” to Extract.
No, it is not just you. I know my chart was accurate at the time it was made, with 10 randomly chosen primers from each box, and that particular lot number. If you read the fine print on the bottom, it will explain that these results could be different with 10 different primers from the exact same box or lot number.
My last purchase of Winchester W209's resulted with measurements that are shorter than previous primers. These are more in line with the measurements of CCI and Fed primers.
It is nice that they are much closer in length, but the big drawback is that the Muzzleloader Manufacturers are making their primer headspace to the maximum primer length. I don't know if this was an engineering change at Winchester, or just the run on this lot number.
I have several custom breech plugs that the headspace was set for several different primers. Now I can use my CCI/FED plugs to shoot these newer/shorter WIN primers, so that is a good thing. However I will not be getting rid of my old WIN headspaced breech plugs, because the next lot of primers might average 0.005" longer than thes new ones again. Of course the longer headspaced breech plugs will shoot all the primers, but I get ZERO blowback with my fitted plugs. Unless you get lucky, the factory OEM breech plugs will probably leak blowback, especially with the shorter primers.
Sounds anal, but I HATE blowback, and I will go to great lengths to keep it out of my rifles.
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