Hello all, I am new to reloading and have a factory 7 PRC Sig Sawtooth rifle with a 24" barrel. I have shot roughly 100 rounds through it and was going to start reloading some of the once fired factory hornady 175g ELDx brass. When measureing the total length of the case and the length to the shoulder using the hornady comparator tool, they are well under SAAMI spec numbers. What should my next step be? Am I just looking to full length size down .002" for the shoulder bump, then chamfer and debur until I need to trim? Any advice will help.
7 PRC Brass Questions
- Thread starter CurrentTX
- Start date
RL338
Handloader
- Mar 23, 2017
- 3,941
- 6,866
Welcome to the forum.
Until your brass grows to the size of your chamber there is no need to bump the shoulder yet. Set your FL sizing die to just size the neck. You can check with your comparator to see if you’re bumping the shoulder.
Until your brass grows to the size of your chamber there is no need to bump the shoulder yet. Set your FL sizing die to just size the neck. You can check with your comparator to see if you’re bumping the shoulder.
- Thread starter
- #3
That's great info, thank you!
Joec7651
Handloader
- Apr 7, 2019
- 1,067
- 1,627
Welcome to the forum! Great advice above. Bump the shoulder when the brass starts to get tight.
- Thread starter
- #5
So I got back home and was able to start prepping brass yesterday. After tumbling and cleaning the brass I tried chambering some brass in the rifle to see if it got that "fill" of the chamber. The length from base to shoulder was 1.895 and the bolt would not close. I compared the factory ammo and the base to shoulder was 1.892. Would it be fair to assume that is the appropriate amount of bump I need then? SAAMI shows the base to shoulder being 1.904- 0.007, is that just a suggestion?
xphunter
Handloader
- Sep 15, 2005
- 1,440
- 2,958
SAAMI is just a number in some ways.
The real key is what your chamber and fired brass actually measure.
Try bumping 1.5 thou from your fired measuring and see how the bolt closes
Try it again a a 2 thou total bump and see if it is any difference.
With Rem's, I take the firing pin assembly out, then you can get a much better feel of things.
I don't know about the Sig's.
Also, just because one piece of brass bumps 2 thou, doesn't mean all of them will.
Find your most stubborn piece of brass and use it as your guideline, that way you don't have any surprises in the field.
Are you going to anneal?
The real key is what your chamber and fired brass actually measure.
Try bumping 1.5 thou from your fired measuring and see how the bolt closes
Try it again a a 2 thou total bump and see if it is any difference.
With Rem's, I take the firing pin assembly out, then you can get a much better feel of things.
I don't know about the Sig's.
Also, just because one piece of brass bumps 2 thou, doesn't mean all of them will.
Find your most stubborn piece of brass and use it as your guideline, that way you don't have any surprises in the field.
Are you going to anneal?
- Thread starter
- #7
I will try that method and work it down little by little. Taking the firing pin out should be easy enough.
Currently, I do not have any annealing equipment. Is that something I should look into?
xphunter
Handloader
- Sep 15, 2005
- 1,440
- 2,958
It depends how far down the rabbit hole you want to go
Now, I anneal after every firing.
There was a time when I never annealed...
Even when I didn't anneal, I had some pretty good accuracy at short and at LR.
It makes your brass more consistent and malleable.
- Thread starter
- #9
I will probably start annealing when I obtain some higher-quality brass. I'm currently using Hornady brass, and I don't mind making a few mistakes. Once the Lapua brass comes out, I will want as much life out of it as possible! Thanks for the input, I will go home and tinker with it all this evening. It's a fun process trying to develop something that shoots well consistently.It depends how far down the rabbit hole you want to go
Now, I anneal after every firing.
There was a time when I never annealed...
Even when I didn't anneal, I had some pretty good accuracy at short and at LR.
It makes your brass more consistent and malleable.
This was my first five-shot group with the factory 175 ELDx ammo, although the velocity was somewhat lackluster at 2,840.
Attachments
xphunter
Handloader
- Sep 15, 2005
- 1,440
- 2,958
Good shooting/Good Start.
Even at that velocity, it will allow you to kill at far away distances, if you do your job behind the gun.
superdrupal
Beginner
- Mar 3, 2025
- 28
- 58
Good advice. That bullet has a high BC and will expand at low impact velocity (1600 fps) so getting another 100 fps is pretty much meanless in the big picture. If it shoots and it's easy on brass what's not to like?
salmonchaser
Ammo Smith
- Dec 13, 2013
- 5,453
- 6,837
Welcome to the edge of the rabbit hole, excuse me. The forum. Wait until you have 20 sets of dies, 20 ammo cans and the false sense “she” doesn’t know what is in the safe. I guarantee “she” does.
- Thread starter
- #14
Update: Took the advice of pulling the firing pin and bumping the shoulder back by .001" till I had a nice smooth bolt close.
All Measured with Hornady Comparator tool base to shoulder lengths:
New factory cartridge: 1.892 (average)
Once Fired Brass: 1.895
Smooth Bolt close Brass: 1.8905/1.891
From there I resized all the once fired brass I have, finished the rest of the case prep and they are now primed.
Going to mess with GRT to find some powder loads and begin ladder testing. Thanks again for everyone input!
xphunter
Handloader
- Sep 15, 2005
- 1,440
- 2,958
Awesome Possum!
Todd NE WY
Beginner
- Sep 30, 2022
- 27
- 78
Welcome to the addiction. Be careful with GRT from what I read it is an excellent program but not without quirks, as a new reloader verifying any data it produces with current reloading manuals would make for an extra measure of safety.
Todd
Todd
- Thread starter
- #17
Thank you for the advice. I am cross-referencing everything I can!
- Thread starter
- #18
The first eight rounds, which were shot this morning, were used to look for signs of pressure before working up. It's probably at my maximum with the N570, so I will back that down. I'm going to explore the nodes I can find in some of the other powders (velocity/impact relation) and go from there!
- Thread starter
- #19
Rem Jim
Handloader
- Jan 7, 2012
- 691
- 11
There is some ADG and PETERSON brass out there That’s as good as Lapua . I use them all but Lapua is not available yet as you probably know . Weatherby has there own ? 
Now be Carefull as all brass is not the same powder capacity
Besides helping to keep your brass from neck cracking after repeated firings annealing keeps the brass factory soft so you will have consistent neck tension .
In my 7 PRC RL26 is an excellent powder and the New Ramshot GRAND is too .
H1000 -Retumbo - LRT also work good
Delends on your bullet weight .
Keep your info coming. I’m off to load some Barnes 145 LRX bullets to see what I can get for speed and accuracy
Cheers RJ
Now be Carefull as all brass is not the same powder capacity
Besides helping to keep your brass from neck cracking after repeated firings annealing keeps the brass factory soft so you will have consistent neck tension .
In my 7 PRC RL26 is an excellent powder and the New Ramshot GRAND is too .
H1000 -Retumbo - LRT also work good
Delends on your bullet weight .
Keep your info coming. I’m off to load some Barnes 145 LRX bullets to see what I can get for speed and accuracy
Cheers RJ
