7mm SAUM Reamers

[dzelenka]

What reamer is everyone using (especially in a long action)? What throat length? What is the OAL of a 180 Berger VLD seated to the lands?

Thank you in advance for your help.

Dan

 

[jamesh]

Something in the neighborhood of a .170" lead will give you around a 3.000" loaded round with the 180 VLD.
The easiest thing to do is load a dummy round seated the way you want it in brass that you have run through your resizing die and send it to Kiff @ PTG.


James

 

[dzelenka]

I was thinking around 3.055" OAL with the 180 VLD. That puts .285" of the bearing surface in the case neck. Too long? To short?

It is a hunting rifle if that makes any difference.

Dan

 

[dzelenka]

My gunsmith spoke to Kiff this morning and was told that freebore of .188" would give a loaded length of roughly 3.055". That doesn't quite jive with the .170" = 3.00". Are there any other factors involved? Lead angle perhaps?

 

[jamesh]

Dan,
The lead on my reamer starts at 2.232" from the bolt face and is the normal 1 1/2º, loaded rounds with the lot of Berger 180 VLDs I was shooting last year (an older lot) measured 2.997 to 3.003. Either the dimensions on the bullet have changed or Kiff gound my my reamer short, either one could be possible. I have been shooting Hornady 162s this year, loaded rounds are nearly identical, the 162s slightly longer.
Clear as mud now ???
Using Kiffs specks a .170 lead would give you a 3.037" loaded round then, if that is just touching. A .020" jump would get you at 3.017 or a .020 jam would get you 3.057.
Without knowing exactly where the bullet will want to shoot it isn't possible to know the exact length your loaded round will be.

James

 

[dzelenka]

I recognize that I won't be able to tell what length my loaded round will be until I experiment with seating depth. When I was speaking of OAL, I was referrencing the length touching the lands to give a point of reference.

I was told to take a round with the bullet seated where I wanted it, coat it with marker, set my calipers to .282" and scribe a mark on the bullet at that point. I then measured from the casehead to the scribed mark. With the OAL at 3.055", the scribed mark was 2.290" from the case head. Is that measurment comparable to the 2.232" measurement you cited in your post? It seems to be. 2.290 - 2.232 = .058. Your OAL of 2.997 + .058 = 3.055". From those calculations, it seems that a .130 lead would give you the 3.0" length.

Very interesting.

Dan

 

[Doug Humbarger]

Is everybody building 7MM SAUMs useing M700 Long actions? What about the M700 actions that were originaly in 300WSM?