Quick Load & barrel lengths

[Nomad47]

When guys speak of barrel lengths, I see some are to the recoil lug and some are to the bolt face (both from the muzzle).
So I got to wondering which measurement QL wanted to be entered in the barrel length box. Obviously, this measurement needs to be accurately entered in order to come up with proper velocities and barrel times.
But after doing a little checking, I think I found my answer. In the box under barrel length is one called bullet travel. And after doing a little math, QL is using muzzle to bolt face for barrel length. Also, bullet travel is from the bullet base to the muzzle.

 

[Jeff A]

I have always used muzzle to bolt face. I believe I found that answer in QuickLOAD.

 

[Nomad47]

Maybe I also should have asked why some guys state muzzle to recoil lug for barrel length.

 

[Jeffvn]

QL responds most accurately for me (in using the OBT node predictions) if I measure from the crown to the boltface using the most specific measurement that I can (meaning 1/16s or even 1/32 if you can discern that level of detail). I run a wooden dowel from the crown until it stops hard against the boltface, then mark the dowel.

It also helps if you use a fired case water capacity, rather than the software default number.

Jeffvn

 

[jfseaman]

Muzzle to bolt face.

QL wants it as it computes bullet travel from that and COAL.

OBT wants it as that is the length of the steal that resonates.

 

[savagedasher]

I just my cleaning rod from the bolt face to the crown. Larry

 

[Dgd6mm]

I just my cleaning rod from the bolt face to the crown. Larry
[/quot

e]


+1

 

[Nomad47]

I have always used the cleaning rod carefully inserted into the muzzle.

Why do some guys state their barrel length as "to the recoil lug"?

 

[savagedasher]

I just my cleaning rod from the bolt face to the crown. Larry
[/quot One thing about me I never have changed. Thank (Don) I need that .
All guns are measured from the bolt face except Wheel guns they use actual barrel length
Larry

e]


+1

 

[jlow]

You guys got me thinking with this thread and I want to share a technique I developed to make barrel measurements easier.

The reason I came up with this is because a number of my rifles have either flash suppressors or compensators threaded on the barrel. The problem with this is of course barrel lengths stops at the crown and not at the end of the device attached to their ends. Since I wanted to avoid having to take these devices off I came up with this idea.

What I did was to buy a small caliber wooden dowel and then put on it a small plastic piece that was part of a syringe cap. The cap is a cylinder with a slightly too large internal diameter. I fixed this by first plugged it with some hot glue and then drilled it out with an undersized drill bit (relative to the dowel). This allow the plastic cylinder to be moved over the length of the dowel but with enough friction so that it will not move on its own.

Once I got this done, I slide the plastic cylinder so that it move down the dowel more than the length of the barrel i.e. if it was a 20” barrel, I moved it to around 19”. I then inserted the dowel/cylinder into the barrel and then when the cylinder stopped at the crown I push the dowel further until it hit the bolt face. This way, when I remove the dowel/cylinder, the true length of the barrel is the distance from the end of the dowel to where the cylinder stopped.

Works like a charm but always measure at least three times to be sure of the correct barrel length. FWIW, none of the three barrels I measured were close to what they were supposed to be but were slightly longer and those slight differences made quite a difference in QL!

The one I made was for a 223 but I found that it can also be used for a 308 by pushing the rod in slightly off center so that the plastic cylinder (which is smaller than 308”) will also be stopped by the crown.

 

[Nomad47]

Same here on barrel length, jlow. My 28" Criterion barrels and 28.125" and my 28" Bartlein barrel in 28.25". I use the measured lengths both in QL and in Chris Long's OBT formula.

 

[jlow]

BTW, thanks for the thread... Before this I was just going by the published numbers..... :