COAL Question???

[M7025-06]

I'm helping my buddy reload for his new Ruger M77 MKII in 280 Rem. He settled on 140 gr. Accubonds and we've found a couple of promising loads which are printing 1''-1.25'' groups @ 100 yds...not bad but I think we can do better.

Anyway...I have a Hornady COAL gauge and found out this rifle has a fairly long throat (I don't remember the exact measurement - it's in his book). The first batch of reloads were all loaded to max SAAMI spec (3.330''), and like I said, found 1 or 2 loads that showed some promise.

In an effort to stay within SAAMI spec, to fine tune the load, I seated the rounds a little deeper and we're finding that's not going to work. The groups are really opening up the deeper we seat 'em.

My question is...is it ok seat longer than SAAMI spec? Before we give up on these bullets, I would like to try and push these bullets a little closer to the lands in hopes of shrinking the groups down a tad. Obviously I'll back down on the powder charge and work back up.

 

[bronco_buster]

A handloader can load to any spec they desire...that's the beauty of handloading. Exceeding SAAMI specs is inevitable when the envelope is pushed for utmost accuracy. Only you can decide YOUR level of comfort for pushing that envelope. For me, I find that most of my precision rifles perform best when bullet ogives are seated 5-10 thousandths off the lands. I've never worried about what SAAMI has to say because my ammunition is being customized to MY rifle. As COAL may exceed SAAMI spec, I also don't resize brass to SAAMI spec either...I use bump gages to get optimal fit in MY rifle's chamber.

Be safe.

 

[witchhunter]

The SAMMI spec is for the ammo manufacturers, not for us. that is so it will work in any gun. I like to start .010 shorter than the lands if it will fit the magazine. Sometimes that is the deciding factor on cartridge length. Seat out until you see the lands marking the bullet and start .010 shorter. But I found my .22/250 likes em .050. Kinda rare for me, but that is what it likes.

 

[M7025-06]

Very good...thanks guys.

 

[jimbeaux82]

You can load to any COAL you desire, but usually (with a magazine fed rifle anyway) you will be limited by the magazine length. So find out what length cartridge will just barely fit in the magazine and if that length does not put you into the lands you are good to go.

 

[gamestalker]

One of the best aspects of reloading for our specific firearms, is that we are able to accommodate the dimensional characteristics, OAL being one of those aspects. SAAMI spec, and OAL shouldn't even be used in the same sentence, in my opinion. Seriously, the only reason to even consider SAAMI spec when it references OAL, is so finished cartridges will fit the magazine, if so desired / needed.

The proper OAL for a bottle neck cartridge is only limited by the distance to the lands, or how much, if any of the olgive is desired into the lands. If magazine fit becomes problematic, or reaching the lands at the desired OAL doesn't provide adequate neck tension, then adjust OAL as needed. If you can pull a seated bullet from the neck, then it may need to be seated a bit deeper, but even that can depend on your specific shooting needs. A common guideline is one bullet diameter minimum, or .284" shank to neck contact for the .280 Rem.. Other wise, seat them as long as you desire.

Note, with bottle neck cartridges, pressures will increase the closer the bullet gets to the lands. So the correct manner in working up a load is to first determine the desired OAL, and then work the powder charge up at that OAL to avoid sudden pressure spikes.

GS

 

[DRYHUMOR]

If your load COAL ends up a bit long for the magazine, single loading is no big deal.

 

[RainDodger]

Kind of weird results in my experience though. I've found that almost universally, my rifles shoot better if the bullet ogive is around .030" off the lands. When I reduce that value to .020" and below, I get occasional weird flyers.

If you're running your bullet just off the lands or touching, remember that pressure goes up... work your loads up to prevent problems.