7mm SAW Cartridge

[Syxx15]

Here is a little update on load development that I conducted over the last week. Please keep in mind that I am no pro shooter. I am just your normal shooter that participates in Provincial and National PR Matches.

Specs of rifle again;
- Curtis Customs Vector Action
- KS ARMS Heavy Varmint 1:8.5 barrel @ 28" and profiled muzzle break
- WTO long throat, .150″ freebore reamer
-MDT ESS Chassis
-Vortex Razor Gen II

First here are a few pictures of my rig;

Now on to the load development. The first bullet I tried was the Hornady 162gr ELD-M. The powder I started with was Varget. For brass, I thought I would try resizing Lapua 308 large rifle primer brass. I am using Whidden FL Bushing sizer and seater die. To neck size down, I used a 325 bushing first and then 309 bushing to final size.

For my range of powder, I started with 40gr for break in load at 100 and then loaded up 10 of 41.5gr, 42.0gr, 42.5gr and 43.0gr. I got my start point for West Texas Ordinance webpage. When I fired all the above loads using resized Lapua brass, I was getting blown primers and brass splitting. My groups were just non-photo worthy that's for sure.

So what did I do next. Well, I got some 7mm Saw Alpha brass from Insite Arms and used the same bullet and powder charges again. This time I used CCI BR-4 primers. Below, you will see pictures of my groups using Alpha brass. My first 10 shots using 40gr of Varget at 100 yards. Powder charges from 41.5gr to 43.0gr were done at 200 yards.

With these groups, here are the speeds that I got with my Labradar;

40.0gr -> 2616 FPS -> E.S = 81, S.D = 24.0
41.5gr -> 2722 FPS -> E.S = 17, S.D = 5.1
42.0gr -> 2757 FPS -> E.S = 21, S.D = 5.8
42.5gr -> 2796 FPS -> E.S = 17, S.D = 4.7
43.0gr -> 2830 FPS -> E.S = 18, S.D = 6.4

Using resized Lapua brass the speeds were faster roughly by 50 FPS. But we know how those loads turned out.

I would say my best consistence group minus flyers was 42.5gr and it measured to be .492 MOA. So now do I fine tone the load from 42.0gr to 42.5gr to see if I can get better results? Or just leave it at that? Or that the Hornady 162gr ELD-M are just not meant for that rifle.

Next load development I am going to testing will be using Berger 168gr VLD. Hopefully, they will have better results.

Thanks for looking and stay tune.

 

[TRDJer]

Did you rent the reamer from WTO or does someone on our side of the border have one?

 

[Syxx15]

Did you rent the reamer from WTO or does someone on our side of the border have one?

EM Precision carries one on this side of the border. They were the guys that did the smith work. Great guys to deal with!

 

[dan belisle]

Did a little research on this, as I was curious. Slightly improved 7mm-08 (though less than a 7mm-08 AI), that uses small rifle primers. To get those velocities with those bullet weights you have to have both long barrels and very high pressures. - dan

 

[rifleman762]

I saw a 224 Valkyrie cartridge for the first time yesterday and didn’t know it was such a tiny case but with those 88 Eldms it could be a decent option for those who wanna save some money

I've used the 88gr ELD-M in a 22 Creedmoor. It easily pushes them to 3200 fps with H4350 in a 25" barrel. Recoil is a hair less than a 6mm 105gr at the same speed. Ballistic coefficient is pretty much identical. BUT... I've never shot in a competition . It's just for fun.

 

[TRDJer]

I’d say the primary benefit of the 7SAW vs 7-08AI is not having to fire form brass. You can either just buy Alpha brass or resize Lapua brass and go. I’m curious to see real world numbers since the 7mms really interest me.

 

[Crashman]

I have had two different 284 wins built in the last few years, both shot very well on long actions with 180 Scenars seated to beyond 3.1". Velocities were 2850-2950 depending on rifle and load. Excellent brass, easy load development and great accuracy would have me build another one if I ever need to scratch the 7mm itch again.

 

[Syxx15]

Hey Guys, just another quick update. I went out to the range yesterday and conducted another load test with the Berger 168gr VLD using Varget. The powder range for the testing was 41.5gr to 43.0gr.

I must say, I had better results with the Bergers compare to the Hornady's. The Hornady's just did not group well for me.

Here are a few pictures from the range yesterday. All groups were fired at 200 yards. I did have flyers on the target that I know that was all me. My best group was .303 MOA with 43.0gr minus the flyer.

Here are the speeds I was getting;

41.5gr -> FPS = 2703, E.S = 35, S.D = 10.4
42.0gr -> FPS = 2731, E.S = 26, S.D = 7.8
42.5gr -> FPS = 2760, E.S = 27, S.D = 7.0
43.0gr -> FPS = 2796, E.S = 10, S.D = 2.7

My next load testing that I will be trying is the Berger 168gr again using H4350. I will be posting results of those groups as well.

Stay tune and Happy New Year!

 

[kthomas]

Berger's have become my go-to bullet. Every time I try to chase BC and the "new shiny" with bullets, I always end up back with Bergers. Stick with them if they work.

Have you done a bullet seating test prior to testing velocity with differing charge weights?

 

[Syxx15]

Berger's have become my go-to bullet. Every time I try to chase BC and the "new shiny" with bullets, I always end up back with Bergers. Stick with them if they work.

Have you done a bullet seating test prior to testing velocity with differing charge weights?

I think I am going to stick with them. Every calibre that I have which range from 6.5 Creedmoor, 6.5x47 Laupa, 284 Win and 7mm Saw, I just can't seem to get the ELD's to group well. I am end up using Sierra's or Bergers.

I haven't done any seat depth testing with them. My first group test with the 168 VLD's was 0.015" off the lands, which just fits in the mag. The next testing I do with them using H4350, I am going to try 0.025" off the lands and hope I have a little more room in the mag.

 

[kthomas]

I think I am going to stick with them. Every calibre that I have which range from 6.5 Creedmoor, 6.5x47 Laupa, 284 Win and 7mm Saw, I just can't seem to get the ELD's to group well. I am end up using Sierra's or Bergers.

I haven't done any seat depth testing with them. My first group test with the 168 VLD's was 0.015" off the lands, which just fits in the mag. The next testing I do with them using H4350, I am going to try 0.025" off the lands and hope I have a little more room in the mag.

If you haven't tested the seating depths, then I don't think it's fair to rule out the Hornady yet. You need to try the bullets jumping at different distances to see what groups best. Just because the Berger shot better at one randomly contrived seating depth doesn't necessarily mean it's going to be the better shooter.

 

[redrams9]

Hi Syxx, been curious if you have done anymore load testing or any other shooting with your 7 saw?
I just ordered a barrel and brass for one from Insite and wanted to hear your ongoing experiences?
Guys in the States, and at WTO, have had good success with Re16, have you tried it yet?

 

[Syxx15]

Hey redrams9,

No I have no tried Re16 for load testing as of yet. Over the last month I did some more load testing with the Berger 168VLD's and Berger 184gr F-Class Open Hybrid. This time, I tried H4350 and this powder gave me better results than Varget. For the 168's I started at 45.5gr and went up to 47gr in .5gr increments. I found my best group was at 45.5gr running at 2772 FPS E.S.=22 and S.D = 7.6. Here is a picture of that group @ 200 yards.

Now for the 184's, I used H4350 and range my test loads from 44.5gr to 45.5gr. I found that my best group was with 45.0gr running at 2708 FPS E.S=27, S.D=7.8. This group was shot @ 200 yards as well.

I think for this barrel, I am going to stick with H4350 for now and see how it does at load range when the season begins. My game plan is to use the 168's to 200-600 yards and use the 184's from 600-1000 yards. Maybe in the future I might give Re16 I tried, if the H4350 does not do well at the longer ranges.

 

[redrams9]

Those both look like really promising loads. Good shooting! Could I ask you a few more questions then...
You are happy with the 7 saw brass? Is it Small or large primer? Did you order the 7 saw dies straight from Whidden?

 

[Syxx15]

Hey redrams9,

Thanks for the kind words. Ask away my friend......I will answer your questions to the best of my knowledge in order, lol

Am I you happy with 7mm Saw Brass?

Here is a little background on what I did when I first started load testing for 7mm Saw. For brass, I thought I would try resizing Lapua 308 large rifle primer brass. I used Whidden FL Bushing sizer and seater die. To neck size down, I used a 325 bushing first and then 309 bushing to final size.

When I did my first set of load testing with resized Lapua brass, I was getting blown primers and brass splitting and not getting good group results. So, overall I would say it is worth getting the 7mm Saw brass. It saves time with reszing and all that neck down jazz and I am very happy with the Alpha brass.

Is it Large Rifle or Small Rifle Primers?

The 7mm Saw brass from Alpha is Small Rifle primers. So far for load testing, I tried using F205M and CCI BR-4. Found that CCI BR-4 performed better.

Did you order the 7 saw dies straight from Whidden?

No, I did not get the dies straight from Whidden. I got them from EM Precision who build the barrel/action. That being said, you can get the dies straight from WTO. They offer Whidden, Redding and Hornady.

I hope that answers your question. Sorry for the long answer for question 1. If you have anymore question, please feel free to ask! I'll be happy to help out the best I can.

 

[redrams9]

Thanks for the info.
After lots of research and discussing specifics with the guys at Insite, we have settled on a 1/8 twist barrel, full 1.25” profile, 28-29”, as I am primarily going to run 180 and 184 gr Berger’s in mine, same bullets as both my 284 Win builds. I’ll try lighter bullets if those don’t work well later. Also ordered Alpha brass and Whidden dies from Insite. The Alpha brass in my Creedmoor is excellent, and have alpha dasher brass coming with a dasher barrel I’m spinning up right now too.
I am going to start my work ups with the heavier bullets with Re16 to start, it is a recommendation of the WTO guys with the heavier bullets, and is also my go-to powder across 4-5 of my other calibers as well. It’s very temp stable which I need, as we try to shoot year round here in chilly AB. If you try Re16, just keep in mind, it runs dirty, but cleans out easy too.

 

[Syxx15]

No problem redrams9. Can't wait to for your results with Re16. What barrel company did you decided go with? Once everything gets put together, please keep me in the loop rather in this thread or PM.

 

[redrams9]

I think I am going to try an X-Caliber this time. I have used tons of krueger's, Benchmarks and Bartliens, and have a Hawkhill being spun up right now, so thought I'd try another button rifled cut barrel, and see how it compares to the others.
I can definitely keep you updated as mine gets going. I have several other barrels for my switch barrel rig besides the 7 SAW, and can compare, in real time, in the same conditions, against several other calibers on the same day.

 

[Syxx15]

Very nice choice. I haven't really done much research on that brand of barrel. Well, today I bit the bullet today and bought a pound of Re16 today. Going to do some load testing with it using Berger 168's. I will keep you in the loop on how I make out. Might as well try the 184's with it too.

 

[redrams9]

I think you’ll love the Re16. From what I’ve read, it is the most temp stable powder out there. I have used it in 6mm stuff, Creedmoor, 6.5x47, and have a great load for my 284 Win barrels as well.
The biggest downside to Re16, is how dirty it runs, and how quick it can form carbon rings. As long as a guy stays on top of that though, it’s been fantastic for me.
Last month I tested Re16 against Varget and H4350, in one of my 6.5x47 barrels, and Re16 produced more speed and lower SDs then the others with all other parameters the same. And no pressure signs at all. Same pattern it seems in every caliber I try it in.