Long Range Hunting Online Magazine


Go Back   Long Range Hunting Online Magazine > Rifles, Reloading, Optics, Equipment > Reloading

Reloading Techniques For Reloading


Reply

7/300WSM Case Capacity and Forming

 
LinkBack Thread Tools Display Modes
  #1  
Old 06-21-2011, 10:29 PM
Bronze Member
 
Join Date: Apr 2010
Posts: 82
7/300WSM Case Capacity and Forming

I am just curious what the typical case capacity is for the 7/300WSM wildcat.

I have been thinking about a 7mm SAUM, but if the 7/300 falls about halfway between the SAUM and the straight 7mm WSM I just might give it a try....assuming case forming isn't too much of a challenge.

Can I just bump the necks down in one step, run a 7mm expander ball through them, and then neck turn to fit my chamber?
Reply With Quote
  #2  
Old 06-21-2011, 11:00 PM
Platinum Member
 
Join Date: Jul 2004
Location: Texas
Posts: 5,207
Re: 7/300WSM Case Capacity and Forming

Quote:
Originally Posted by 300magman View Post
I am just curious what the typical case capacity is for the 7/300WSM wildcat.

I have been thinking about a 7mm SAUM, but if the 7/300 falls about halfway between the SAUM and the straight 7mm WSM I just might give it a try....assuming case forming isn't too much of a challenge.

Can I just bump the necks down in one step, run a 7mm expander ball through them, and then neck turn to fit my chamber?
The 7/300wsm has less case capacity than eather the 7mmSAUM or the 7mm WSM.

IMO. There really isn't any reason to go with a 7/300 and deal with the problems of having a
wildcat that does not exceed a factory round.

The 7 SAUM or the 7WSM will push heavy bullets faster and can be loaded down to mild loads
as low as the 7/300 can.

You can buy ammo for ether the SAUM or the WSM but not for the 7/300 and that can be a big
advantage in my opinion.

J E CUSTOM
__________________
"PRESS ON"
Reply With Quote
  #3  
Old 06-22-2011, 07:55 AM
Bronze Member
 
Join Date: Apr 2010
Posts: 82
Re: 7/300WSM Case Capacity and Forming

I didn't really want to use the straight 7mm WSM because the extremely short neck makes it next to impossible to seat long VLD type bullets out far enough to not contact the neck/shoulder junction, even in "WSM" length actions. (And I don't want to use a long action)
Also the straight WSM has a huge case capacity (81.5g if memory serves) which seems to be beyond what is necessary to get big VLDs up to the speeds I want to reach.

As for the SAUM, I was sure that it was the smallest of the group...I have never formed a 7/300 so I can't say from experience what its case capacity is, but all the research I have done had lead me to believe that it was still larger than the SAUM (@ approx 73gr)
I was hoping the 7/300 was in the middle of the two, and I wasn't really concerned about it not being a factory round, because from everything that I hear, neither is the 7mmSAUM anymore....though maybe new ammo will continue to be made for a time, even if new rifles aren't.
Reply With Quote
  #4  
Old 06-23-2011, 09:41 PM
Silver Member
 
Join Date: Oct 2008
Location: Bryan, Tx
Posts: 284
Re: 7/300WSM Case Capacity and Forming

The advantages of the 7/300 are not case capacity. I chose this round for what I am able to do with the neck compared to the 7wsm. Just cause u can cram more powder in a load does not make it more accurate. Availability of Norma 300WSM brass also helped to make my decision. My 7/300 will outshoot every 7wsm I have seen. However, someone with good rifleman skills could likely outperform my 7/300 with a .308. Hold/technique is everything.

I perform case capacity tests with an "empirically derived" combination of DSS and H2O to minimize H2O tension. Plain water capacity tests are hard to duplicate since the meniscus of plain water (and therefore weight) varies between users and between tests.

My sweet load uses 66.2 H1000 behind a Berger 180g at 2950fps with fed215m primers and near perfect brass. I can get more powder in this case, but groups open up pretty quick. Just because a wildcat doesn't "exceed a factory round " doesn't really tell the whole story. A keen handloader will maximize advantages that will outperform any factory loads available. Good handloads in a factory chambering will also perform well, but the amount of work is the same. Crappy factory ammo in a custom gun will still give crappy results.
Reply With Quote
  #5  
Old 06-24-2011, 12:19 AM
Platinum Member
 
Join Date: Jan 2011
Posts: 2,096
Re: 7/300WSM Case Capacity and Forming

With the reamer blueprints I looked at a 7/300wsm is virtually a 7mm wsm they are the same length all you are doing is necking down a 300 wsm to 7mm. 300wsm blueprint shows 80.4grns capacity, 7mm wsm shows 80.3grns, 7/300 shows 80.1, the only advantages is good 270/300wsm brass verses winchester brand 7mm wsm brass, to work the brass less I'd get 270wsm norma brass and neck it up, your only expanding .007". But yet these with vlds will not fit in a remington sa.
Reply With Quote
  #6  
Old 06-25-2011, 09:17 AM
Platinum Member
 
Join Date: Jul 2004
Location: Texas
Posts: 5,207
Re: 7/300WSM Case Capacity and Forming

Quote:
Originally Posted by backwoods83 View Post
With the reamer blueprints I looked at a 7/300wsm is virtually a 7mm wsm they are the same length all you are doing is necking down a 300 wsm to 7mm. 300wsm blueprint shows 80.4grns capacity, 7mm wsm shows 80.3grns, 7/300 shows 80.1, the only advantages is good 270/300wsm brass verses winchester brand 7mm wsm brass, to work the brass less I'd get 270wsm norma brass and neck it up, your only expanding .007". But yet these with vlds will not fit in a remington sa.

Just to clear it up.

The 7mm WSM is different than all of the other WSMs and uses it's own head space gauge.

The 300 WSM has a body length of 1.802 and the 7mm WSMs body is 1.856 (.054 longer)

The neck is shorter (.244 compared to .298 of the 300) but is not two short.

It is .020 shorter than one caliber .284. And The tried and true 300 Win Mag has a neck length
.044 shorter than the caliber (.308 ) so it has a shorter neck based on the bullet dia than the
7 WSM.

All of the WSMs are the same OAL so you can make any caliber from any of the WSM brass if
you want to go to the trouble of resizing and fireforming.

In fact , Norma makes brass for the 270 and the 300 WSM an I had thought about buying some
300 WSM Norma brass and turning the necks and sizing it to 7mm WSM then fireforming it but
the Winchester brass with careful sorting and case prep has worked very well, and the accuracy
at 100 yards with 5 shots in a sporter weight custom rifle was .174 (best) and .212 (Worst)
with a 140 Accubond @ 3307 ft/sec.

I know that the accuracy could probably be improved with a different bullet/powder combination
but For hunting It shoots as well as I can under those conditions.

If I wanted to size down I would go to the 7/08 or the 6.5x47 lapua, Both are capable 1000 yard
shooters.

Again, just an opinion.

J E CUSTOM
__________________
"PRESS ON"
Reply With Quote
  #7  
Old 06-25-2011, 12:17 PM
Platinum Member
 
Join Date: Aug 2003
Location: NC, oceanfront
Posts: 3,031
Re: 7/300WSM Case Capacity and Forming

This what I come up with [PICs]
from 7WSM to 7/300WSM you gain .038"neck
From 7WSM to 7SAUM you gain .068"neck

The 7SAUM is ~6-7gr less capacity
Attached Thumbnails - Click to View Larger
7/300WSM Case Capacity and Forming-7saum.jpg   7/300WSM Case Capacity and Forming-7wsm.jpg  

7/300WSM Case Capacity and Forming-7-300wsm.jpg  
Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes


Similar Threads for: 7/300WSM Case Capacity and Forming
Thread Thread Starter Forum Replies Last Post
Case capacity lever-hed Reloading 3 07-21-2009 12:31 PM
Case Capacity JDT Rifles, Bullets, Barrels and Ballistics 1 12-18-2005 02:19 PM
Case capacity of 338... trader388 Rifles, Bullets, Barrels and Ballistics 5 12-01-2004 07:55 AM
Case Capacity 7ultra Rifles, Bullets, Barrels and Ballistics 6 10-11-2004 11:21 PM
case capacity 308 nate Rifles, Bullets, Barrels and Ballistics 1 01-09-2004 03:43 PM

Current Poll
Do You Think Slingshots Should Be Legalized For Hunting Brown Bear?
Yes - 47.58%
845 Votes
No - 52.42%
931 Votes
Total Votes: 1,776
You may not vote on this poll.

All times are GMT -5. The time now is 10:50 PM.


Powered by vBulletin ©2000 - 2014, Jelsoft Enterprises Ltd.
Content Management Powered by vBadvanced CMPS
All content ©2010-2014 Long Range Hunting, LLC