7 Saum freebore for short action

[tho98027]

Going to do a switch barrel with my surgeon scalpel. Currently chambered in 6.5 creedmoor. Going to order a mag bolt and do a switch barrel with a 7 Saum. What is the ideal freebore to shoot the 180's in 7 Saum in a short action. Planning on either 183smk's or 180ELD's. I need to order a reamer. Planning on using norma 7 saum brass. Any advice on neck diameter. Do not want to neck turn. Appreciate any advice. Thank you.

 

[RampedRaptor]

Do you plan to load magazine length or are you going to single feed them ?

 

[tho98027]

Planning on using accurate mags which allow a coal of 2.94". I understand I can get more performance from a long action or single feed from my short action, but I prefer using a magazine.

 

[Sendit6.5]

Reach out to Dave Kiff at PT&G and have him design a reamer for you. He's a great guy with a lot of knowledge that's always willing to help!


Sent from my iPhone using Tapatalk

 

[WarbirdWeaponry]

My SAAMI reamer puts the 180 ELDs on the lands at 2.95."

 

[Mordamer]

SAAMI reamer spec is .090" freebore if I remember correctly. You probably want one at about .050" freebore for the 180's so you have some wiggle room and can chase the lands in the future.

 

[tho98027]

Thanks fellas. .050 sounds like what I need.

WarbirdWeaponry, what kind of muzzle velocity are you getting with the 180 eld? What powders have you found to work well for you. Thanks again.

 

[WarbirdWeaponry]

Thanks fellas. .050 sounds like what I need.

WarbirdWeaponry, what kind of muzzle velocity are you getting with the 180 eld? What powders have you found to work well for you. Thanks again.

I have only tried Reloder 25 as I bought a bunch of it on sale. Out of my 24.5" bbl there should be a large accuracy node around 2870-2900 fps. I haven't shot enough to have a good sample of accuracy and ES but it looks promising for the barrel I currently have (#5 Shilen 1-8). With Norma brass 61.5gr should be about right.

 

[.50 Cal Cow]

How temp stable is the RE25? Is your loads for SA magazine length?

Would be interested to look into it if so.


My 7SAUM with the 180 hybrids seated to where boattail starts is just around the neck shoulder junction. With a 24" barrel and 60.9 grains of H4831SC had me at around 2855-2860fps the other day.


The chamber was originally throated for a SA magazine and I struggled to get 60.0 grains of H4831SC into the case with the 180 hybrid and even less when I tried the 175 ELDX.

 

[Barney88PDC]

I can tell you with a 0.180" FB it puts the base of the bearing surface of a 180 VLD at the neck shoulder junction and you are kissing the lands. This is at 3.030" OAL so too long for a SA.

So I don't see how a 180 Hybrid is going to be perfect with only 0.050" FB. WIth that short of a FB it would seem the bullet would be well into the case just to be able to chamber a round.

 

[Mordamer]

I can tell you with a 0.180" FB it puts the base of the bearing surface of a 180 VLD at the neck shoulder junction and you are kissing the lands. This is at 3.030" OAL so too long for a SA.

So I don't see how a 180 Hybrid is going to be perfect with only 0.050" FB. WIth that short of a FB it would seem the bullet would be well into the case just to be able to chamber a round.

It won't be perfect, but it is what is necessary to run 180's from a mag in a short action. What is wrong with seating the bullet deeper than the neck shoulder junction?

 

[Barney88PDC]

You chew up room in the case where powder can go. Hence, less speed, possibly to the point where the greater speed of a 168 might overtake the BC and lower speed of a 180. Every barrel is different so which is best would really depend on his barrel and his chamber. No doubt a 180 will come out the end of the barrel even if the bullet is deep in the case and the MV is slow. It just may not be optimal.

 

[dino67]

I've got a 7mm SAUM built to run as a short action on a Tikka T3 Action. Uses Accurate mags without front plate. Running 180gr Berger Hybrids at 2900fps from a 27" barrel using retumbo. The rifle is a hammer and makes the run out to a mile look easy. COAL is 2.950" with the hybrid. Can't remember the freebore spec but will try and dig it up from my pile of notes.

 

[3rdfocal]

I have only tried Reloder 25 as I bought a bunch of it on sale. Out of my 24.5" bbl there should be a large accuracy node around 2870-2900 fps. I haven't shot enough to have a good sample of accuracy and ES but it looks promising for the barrel I currently have (#5 Shilen 1-8). With Norma brass 61.5gr should be about right.

I'm seeing a good node around 2850-2900 with the 180 ELD as well. 7828SSC powder though.