COAL question

[coonsmen]

I had a rifle rebarreled by a well respected gunsmith on this board and when i got it back The only problem with it is the coal is supposed to be 2.80 (260 rem) how ever I have to set the bullet back to 2.730 before it's not contacting the lans (used smk bullets). Will this pose a problem with with load work ups and over pressure issues if ran at the same recommended charges in the reloading manual(if I run a coal of 2.73). Ive Never ran into this before so I'm unsure.
thanks
Jeff.

 

[Fursniper]

The only thing the COAL is good for is whether or not the cartridge will fit in your magazine. CBTO is the measurement that matters for loading. Pick up a Hornady OAL guage, the bushing insert for a 260, a decent set of calipers and a 260 modified case and you can then start working up a load with the measurement that actually matters. An average distance off the lands for many as an example is .020. Yours will depend on the sweet spot that your barrel likes for the type of bullet you will be shooting. COAL means nothing. The instructions with the guage should get you started. Keep in mind that reloading manuals as a rule are very conservative. Having said that, the best advice is start low and work up. Keep watching for pressure signs. Most guns shoot their best under the maximum load. Jammed into the lands will give you more pressure than a bullet set back a bit (doesn't mean it won't shoot better or worse though, again, depends on your barrel, etc). That should get you started.

 

[Ajwillly]

+1 to the gentleman above. To add on to it the only downside is the case capacity with the bullet seated deeper. So play it safe and back off the recommended loads for sure. Unless you're dead set on SMK you can also try other bullets for more case space. For my rifle in 300WM I could seat 208gr hornady ELDs out about 40thou further than the 190 SMK. Also to add on, to watch for pressure I start with 40thou off the lands then bump to 20thou off once I look at the pressure signs.

 

[coonsmen]

thanks alot for the replies gentlemen!! you have cleared my worries!!!

 

[lash]

If you are talking about 142 SMKs, it would explain it a bit. Those are shaped in a way that you have to throat a bit longer for them if they are your primary choice for loads. That's why some gunsmiths will ask you what projectile you plan on using. Check out the Hornady 143 ELDs, either the 139 or 136 Scenars from Lapua or one of the Berger choices. These all have a sleeker ogive profile and will allow you to load longer if that's what you want.

 

[coonsmen]

They are the 140s. I'm only set on them because I have 500 or so. Once I'm out I'll go back to the 139 scenario, and see. Did a later test last weekend and had no pressure issues up to 42 grains (did not go higher in the test) of h4350. Best group at 200yds was at 41.5 grains set back 20 thousands so I'll stick with that for now .
Thanks a lot for the advise.