Bore riders?

[borg]

On a bore riding 30 cal, do you want a loose or snug fit?
With PC, they are just snug, but don't have to apply pressure to go to the bands.
W/O PC, they are a loose fit.

[Yodogsandman]

Sounds like you have a bore wobbler. Which bullet mold and which exact caliber?

[borg]

I have two, a Lee 230 R5 at .295, and the Lyman 299 100 gr .299.
Would the PC make up the difference?

[Yodogsandman]

Huh? Yes, PC will help a lot, if you pre-heat your boolits first and then PC, it will give a heavier coating. I just ESPC'd some SKS boolits to add .002". The Lee 312-155-2R cast at .3125" and I need .314". I didn't get enough on cold (30*F) but, they did shoot better with the added thickness. Pre-heating to 400*F, I can get .006" more thickness. I really don't need that much but, you might depending on your chamber and bore size.

Have you slugged your chamber so you know what you need to add?

[borg]

I did a chamber cast, bore is .308, but can't measure the lands, 6 grove.
The coated boolits are a SNUG fit down the muzzle with one BBTC coat, would that be enough to ride the lands?
I've casted for many years, but only for pistol that don't require the exactness of rifle boolits for accuracy.

[Le Loup Solitaire]

Bore riders do especially well in situations where the lands occupy at least half or more of the circumference of the bore. The O3-A3 with its two groove barrel and the 1917 with its 5 groove rifling are good examples. The nose section should measure .301 and the bullet body should be .310 or .311. If the bullet dimensions are less/undersize then you will get a tilting of the bullet as it goes down the barrel and it will exit the bore in that cockeyed posture which results in wild shooting. This subject is addressed by E.H. harrison in his investigation of 30 cal behavior in the NRA Handloading Handbook viewable in Cast Pics on this forum. LLS