6mm reloading: am I missing something?

[topclass2017]

While I'm not new to reloading, I am fairly new to reloading the 6mm BR.

I'm loading Bergers, 80g and 88g FB Varmint. The Berger book calls for a COAL for both bullets of 2.441". Believing that the only dumb question is the one not asked, I pose the following:

How do I get to 2.441" with sufficient bearing surface when the 80g bullet is only .915" long, the 88g is 1.070" long, and a prep'd case in 1.550" long? For the 80's I'd have .024 of bullet within the case and .139" for the 88. Seems rather skimpy! And if I load the bullet deeper in the case the jump is going to be huge.

Am I missing something? What do those of you who load 80's or 88's do? What length do you load to?

 

[Doug Beach]

Ignoring the book, for the moment, have you determined where those bullets would need to be seated to contact the lands in YOUR rifle?

 

[Sniper338]

Completely ignore the COAL in any book. It is irrelevant. You have to measure your rifle chamber and determine the seating depth for your rifle and those bullets.

 

[Sundown]

Exactly what are you doing...Varmint or Competition? Are you using a magazine fed or single shot shooter. If magazine fed shooter you want the coal to be length to fit magazine even though it may not be the most accurate load. If single shot you want to find the most accurate seating depth. I have a shooter that is deadly accurate out to 600 yards that jumps .050" with a 90 Gr bullet. A general rule I use is to have at least half the diameter of the bullet measurement length seated in the brass. So with the 6 BR with a diameter of .243", you would want .122" seated in the brass.

 

[Ranger188]

As the others have said. Who knows what your freebore is on that chamber.
You need to measure the bullet(s) that you want to use and see what they measure
to the lands and then go from their with seating them for jump.

 

[kthomas]

Completely ignore the COAL in any book. It is irrelevant. You have to measure your rifle chamber and determine the seating depth for your rifle and those bullets.

I couldn't tell you what the book values for COAL is for any of the cartridges that I reload for.

All that matters is what works for your rifle and whatever that measurement ends up being with your measuring equipment.

 

[Sniper338]

Completely ignore the COAL in any book. It is irrelevant. You have to measure your rifle chamber and determine the seating depth for your rifle and those bullets.

Just to add to my post... if you change bullets, you need to remeasure too. And after shooting for a while and you notice groups opening up remeasure because your lands get worn down and the throat get linger over time, ie. "Chasing the lands".

 

[powderbrake]

topclass2017:
I also shoot the 88 gr Berger in my 6BR, and your numbers look very strange to me.

You stated that with the 88, a 1.550 trim length, you only have .139 in the case, and if you seat them in further, the jump will be excessive. I am assuming those are "calculated numbers" based on the loading book numbers, the length of the bullet, and the length of the case.

My freebore is .104, my "touch point" (using the "Wheeler Method"

) is 1.799, and my loaded base to ogive distance is 1.804 (.005 into the lands). With these numbers I get the 88 Berger almost all the way down the neck, with a 1.550 trim length. So I assume you either have 1) a REALLLLLY long freebore, or 2) you are pushing the bullet WAYYY into the lands.

OK, forget about COAL as others have said, if it fits your magazine and feeds, it's OK

What you need to measure is the distance from the ogive (where it first contacts the rifling) to the base of the cartridge. You must have a Bullet Comparator and a measuring caliper. https://www.midwayusa.com/product/101273351?pid=231904. I suggest you start with the bullet just touching the lands, so you can either go longer (into the lands) or shorter ( jump), as you do your range testing for accuracy.

The picture on this page https://www.hornady.com/reloading/p...s-and-gauges/lock-n-load-bullet-comparator#!/ shows how the comparator is used. It also shows the "Hornady lock and Load" tool , the red thing in the left end of the case. This is used to find the lands, but is not as repeatable as the Wheeler Method. I own a lock and load, but I use the wheeler method. You do not have to have a "lock & Load" tool.

Remember that a bullet comparator measures from the base to the ogive BUT....... that number is for that specific bullet comparator, as the diameter of the hole in the comparator varies from unit to unit, so ONLY use that ONE comparator to do all your measuring. Your comparator would get a different number measuring one of my loads..... very close.... but not the same.

Do you know the throat length of your rifle? Is it a factory rifle or a custom chambered barrel. If so the gunsmith could advise you of the freebore.

 

[topclass2017]

Thank you all for your insights. Very helpful. I had a chance to take some measurements tonight using a Sinclair Seating Depth Gauge. Turns out for my rifle the Berger book value would have resulted in a bullet waaay into the lands. I will spend some time on the reloading bench later this week and load based on calculated base to ogive for my rifle.

 

[Lone Hunter]

Thank you all for your insights. Very helpful. I had a chance to take some measurements tonight using a Sinclair Seating Depth Gauge. Turns out for my rifle the Berger book value would have resulted in a bullet waaay into the lands. I will spend some time on the reloading bench later this week and load based on calculated base to ogive for my rifle.

Why don't you try some Cerrosafe. You can pretty much see what your Freebore would be off the cast.