Book COL sucks!

[Dogleg]

I did the same with factory Federal 6.5x55 ammo 140 Partitions.Shooting a Win 70 FWT got 1 1/2 groups so I bumped the bullets out with a kinetic hammer and set them just shy of the rifling under 1/2" groups at 100 yards and still room in the magazine. Did up the 100 rds I had as I needed brass at the time as well.

I had a similar experience awhile back with a 300 WSM. A local gunstore that was changing directions had a pile of factory they were blowing out. The ammo was cheaper than empty brass so I bought it all. Maybe 20 boxes or that, and aboutvth esame of 7 WSM.
Trouble was; groups were around 3 inches; not worth the barrel wear to blast them off. Before pulling it all down, I took one apart and measured the COL to the lands. The Kimber had a decent length mag and I was able to at least get close to the lands and still have a repeater. That involved bumping them ahead with a kinetic puller and reseating over 100 thou longer.

Without any other changes they shot easily under MOA for a box worth of groups.

Trouble is that changed the status from “not worth shooting” to “Too good to waste”.

The irony is sickening sometimes.

 

[Ganderite]

I had a similar experience awhile back with a 300 WSM. A local gunstore that was changing directions had a pile of factory they were blowing out. The ammo was cheaper than empty brass so I bought it all. Maybe 20 boxes or that, and aboutvth esame of 7 WSM.
Trouble was; groups were around 3 inches; not worth the barrel wear to blast them off. Before pulling it all down, I took one apart and measured the COL to the lands. The Kimber had a decent length mag and I was able to at least get close to the lands and still have a repeater. That involved bumping them ahead with a kinetic puller and reseating over 100 thou longer.

Without any other changes they shot easily under MOA for a box worth of groups.

Trouble is that changed the status from “not worth shooting” to “Too good to waste”.

The irony is sickening sometimes.

The real irony is that many handloaders use the "book" OAL and are creating ammo much like your original factory ammo. It ill go bang, but it is capable of so much more by seating longer, to better suit the magazine and chamber.

 

[Janeau]

The book col is SAMI spec for ammo that will fit in any gun- pending you are using the same components the data was using.
Col is very unreliable and it is given mostly for gun with magazine - internal or external.
CBTO is what you want to use to measure from touch land to jam and below.
Only CBTO - cartridge base to ogive will give you a reliable distance from the land.

 

[DGY]

I guess I don’t have that problem since I shoot ruger no1’s... but not having a bolt to push the ammo in to “sit” the bullet to start with might complicate things??

 

[mbogo3]

One thing to love about certain rifle designs. A decent magazine inside length.
No worse combination than a short magazine and a long throat, IMHO. Dave.

Corlane built a buddy a .300 RUM on a Borden action with a detachable mag ,but like you said with too long a throat so at best accuracy the bullets don't fit the magazine.In essence a single shot.A waste of metal.

 

[iron cat]

I guess I don’t have that problem since I shoot ruger no1’s... but not having a bolt to push the ammo in to “sit” the bullet to start with might complicate things??

I size a dummy round so it will just go to jam when closing the lever in my Rugers.
Make sure you lube the bullet ogive with sizing wax so it will come out when you open it up, but the bullet will stay in the case where it was seated.
You can also use one of those fancy bullet OAL gauges like Stony Point/Hornady makes, but it is not needed if you do it properly.
Cat

 

[bearhunter]

The "Book" COAL is for THEIR rifle. It is assumed that you will measure your own rifle and seat appropriately.

If you shoot the gun a lot, the throat will advance with wear. My 308s need about 5 thou longer each summer.

I'm glad you posted this. Most shooters don't even twig onto the fact that the throats will advance as the round count goes up.

That's one reason why people that buy expensive rifles, such as Cooper's or from some other commercial custom rifle maker get upset when their rifle, properly cleaned, starts to lose accuracy after 500 rounds, or less, depending on the cartridge it's chambered for. The bigger the case and the smaller the bore the faster the throat erodes.

I have a couple of rifles that are very accurate and I will admit I load them much hotter than suggested in the loading manuals. I can get away with this because they're strong, modern actions chambered for old cartridges.

I measured the throat on my Tikka T3, chambered for the 6.5x55, because I noticed the groups were opening up a bit. POI was the same. It had worn appx .007 after 450+ rounds. It also did the same thing, appx .005 after the first hundred rounds. Not unusual.

It's a bit of a misnomer to say the "throat" is wearing. But most people can visualize what is meant. It's actually the "leade" or the tapered surface of the land that wears. Yeah, splitting hairs.

Eagleye, if the throat tolerances in your chamber are tight enough, long throats aren't as much of a problem.

I was a bit skeptical at first, but when I ordered my Palma Match 308 reamer, a knowledgeable good friend convinced me to get a reamer that would cut a throat .0015 over bullet diameter. The throat in that chamber measures .3095 and it's one of the most accurate rifles I own, even though the barrel was a take off that I took a chance on when buying. IMHO, that tight throat dimension makes a lot of difference, especially for a rifle that may be used to shoot everything from short light bullets for caliber or long heavy bullets for caliber and anything in between.

 

[DGY]

I size a dummy round so it will just go to jam when closing the lever in my Rugers.
Make sure you lube the bullet ogive with sizing wax so it will come out when you open it up, but the bullet will stay in the case where it was seated.
You can also use one of those fancy bullet OAL gauges like Stony Point/Hornady makes, but it is not needed if you do it properly.
Cat

Thanks for that, just got my kit the other day and hopefully today I will be able to have it all set up and start reloading! Lots to
Learn yet!!

 

[Boomer]

One thing to love about certain rifle designs. A decent magazine inside length.
No worse combination than a short magazine and a long throat, IMHO. Dave.

When that fails, an H&H length box, follower and bolt stop come to the rescue.

 

[coldmaker]

Don't forget you can skip right by seating depth nodes. I do 0.003" at a time.

i’m beginning a load for my daughter’s 7-08, and i was planning to try this method for the first time (0.003" increment)
in how many groups do you normally find a load?
other methods change OAL by as much as .120"...
this would require an awful lot of round if for exemple the sweet spot is at 0.080" and you go by .003" increments

 

[Leatherstocking]

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

Berger is suggesting some big jumps in seating depth. .04

 

[Lead hammer]

They mention big jumps to get close ish, then small jumps. 0.002-005"

 

[Dogleg]

https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/

Berger is suggesting some big jumps in seating depth. .04

They changed their tune when they realized that there was more money in selling the odd box of bullets to a million hunters than a lot of boxes to a couple of target shooters.

 

[wasrupzuk]

I've been following the Hornady book COL,

Now I might be wrong, I haven’t gone and dug out my reloading book prior to typing this... but if I recall correctly the books state “Minimum COAL”, no where does is say “recommended COAL”.
While this length has much to do about things already discussed here (mainly fitment) I don’t believe it’s their only concern.
I believe they are also worried about pressure if it was made shorter.
The book states a minimum length, a specific bullet, a specific powder and the minimum & maximum amount of powder to stay within safe pressures given that COAL for that bullet used in that cartridge.
Change COAL length and you change the size of the cavity behind the bullet which effects pressure.
The book keeps you safe, not necessarily accurate.
YMMV,
Cheers

 

[Leatherstocking]

The "Book" COAL is for THEIR rifle. It is assumed that you will measure your own rifle and seat appropriately.

If you shoot the gun a lot, the throat will advance with wear. My 308s need about 5 thou longer each summer.

think this is important.
If you read the whole thread, you’ll see one method of measuring max COAL for your rifle.

 

[canthitathing]

Most seating dies use a 20 threads per inch pitch on the seating stem thread. Some micrometer dies are a bit finer thread pitch. Anything with a 20 pitch thread one turn is 0.050”, 1/2 turn is 0.025”, 1/4 turn 0.00125”. There is always abit of slop in the thread, so depending if the dies have a lock ring on the seating stem(redding rcbs) the tension on the threads can make a couple thou difference.

1/4 turn should be 0.0125 in above listing

 

[fuzzy39]

I usually load up dummy rounds as long as the go then back off to magazine length and to make sure I don’t get a round stuck and end up with powder all over.... this happened once to me with a tight chambered Browning. Won’t make that mistake again, haha.

Weatherby’s I have to be a different breed. I tried to load some long in my 257’s and found the accuracy to suffer. When I went back to Weatherby factory ammo COAL, it would shoot the lights out.

Google Erik Cortana, he has some great videos on YouTube of practical handloading for accuracy.