Gunsmithing 7RM + 180 ELD-M reamer spec questions

[ChubbySquirrel]

Greetings!

I'm building a rifle this winter but have some questions in regards to reamer selection or creating a dummy round to have blueprinted for reamer design. 7 Remington Mag caliber (new to me caliber....I'm a 260 shooter traditionally) and I'd like to shoot Hornady's 180 ELD-M at about 2900 fps with H1000 and Federal brass. This will be a magazine fed rifle (Defiance action, AIAX LA chassis and mags) so OAL is of concern. I figure that I'll be rebarrelling this rifle annually, so I'd really like to own the reamer.

What I need:

- Match chamber
- Throat for ELD-M 180's
- Room to chase lands
- Conscious of magazine length requirements
- No neck turn brass

I don't want to reinvent the wheel, just get an optimal design for a popular bullet that someone has figured out already.

I refuse to order from PTG as their customer service seems to have gone sideways. I did contact JGS and they told me to prepare a dummy cartridge that data could be pulled off of for the reamer...BUT I have no idea what seating depth I can get away with for the speed I want and how the throat and jump to lands might play out. Seems too easy for me to mess up and I'd rather not. The gunsmith who will be building it doesn't have a reamer for exactly what I want...plus I'd just like to own it anyway.

Suggestions? I'd be happy with a reamer spec order number or some specific case dimensions.

Thank You,
CS

 

[Sonic Crack]

First off, GREAT idea not goin PTG!!! I would go with the CIP length chassis and mags. Extra room never hurt, should be plenty of length for the RM. mock up a round with ideal neck/shoulder junction and check the COAL VS mag max. Load up your dummy round and send it off. You can spec freebore however you want. Remeber that you DONT have to be close or touching the lands to have a accurate load. I like .004”-.006” loaded neck clearance and throat 001” over bullet dia

 

[7mmFanBoy]

saami spec plenty of room for magazine feed sierra 183, berger 195 , 180 eld using magpul magazine. Stretch it out .15-.2 further out not sure what will be gained case capacity few grains left for max. my load 28" krieger 1:8.5 3000fps 180eld 67g h1000 , max capacity 70g those bullets. Throat my 338 edge +p utilize more case capacity

 

[Clark]

I have a couple 7mmRM reamers of the garden variety.
But my custom reamers from PTG [6mmBR] or Manson [223], I could pick the over all length.

I know when I handload 7mmRemMag, I ignore the SAAMI registered numbers of 61 kpsi and 3.29".
I load more like 72kpsi and 3.34". That works with my factory 7mmRM rifles and the ones I built

 

[lennyo3034]

I load 180 ELDm to 3.495", which is about .025" jump to the lands. My chassis is non-CIP and limited to 3.630" or so. I get 3020 with retumbo out of a 30" barrel. A friend gets a similar velocity with a 28.5" barrel. Neither of us have tried H1000.

 

[fdkay]

I would suggest you look at the 7LRM.
Much better performance and no retarded belt.

 

[ChubbySquirrel]

Isn't mag length 3.5" (least for magpul mags) Lenny? That doesn't give me any room to chase lands in the future. My chassis is the 338/CIP version. 28" bbl sounds about right.

Thanks FanBoy for you intel. That looks about what I'm after.

Yea Sonic, I'd like to jump 0.010, at least it what I've been comfortable with in the past in other, stupid accurate loads.

 

[V-Ref]

RBros has a 7RM reamer that shoots like a dream even with the "retarded" belt. I'd give Travis a call.