WSM Comparison at 20 Inches.

[CMBTshooter]

I'm considering building a WSM on an intermediate length zastava mauser action. I'm considering the 270, 7mm, and the 300 but it's going to come down to which maintains the most performance at shorter barrel. I think my max barrel length will be 20 inches. Which cartridge do you all think would give up the least performance out of this barrel?

 

[DrMike]

From http://www.saami.org/specifications_and_information/publications/download/206.pdf:

Muzzle Velocity between 2501 and 3000 fps and barrel length between 20 and 26 inches, anticipate ~ 20fps change in velocity for each one inch of barrel length. For muzzle velocity between 3001 and 3500 fps and barrel length between 20 and 26 inches, anticipate ~30 fps change in velocity for each one inch of barrel length.

 

[SJB358]

I would think the 300 would be my pick were I going with a 20" barrel though. Seems like it would have the least amount of loss for that short barrel. Just my thoughts though.

 

[DrMike]

What is your purpose for this particular rifle? That could have some bearing on which cartridge to chamber. Given similar weight bullets, I don't believe the difference in performance would be significant between any of them.

 

[Vince]

I thought the WSM calibers were specifically designed around the 24" barrel?

If so why do you want to shorten it so much? Wouldn't you maybe be better served by a non-WSM caliber?

 

[Anonymous]

I thought the WSM calibers were specifically designed around the 24" barrel?

If so why do you want to shorten it so much? Wouldn't you maybe be better served by a non-WSM caliber?

I gotta wonder the same thing.... With a 20" tube would a .300WSM outperform an '06? It likely would but the margin would get a lot smaller I'd bet.

 

[CMBTshooter]

I wouldn't be upset with 30-06 performance. The main reason for this is that I have an intermediate length action. I was going for handier than my 300 win mag and more punch than my 308 Win. Maybe a 350 rem mag would be a better option.

 

[muleman]

I would think the 300 would be my pick were I going with a 20" barrel though. Seems like it would have the least amount of loss for that short barrel. Just my thoughts though.

+1, Use faster powders/ check Q/L for estimated% of burn.
A 150gr NAB or BT loaded with Superformance should get 3200-3250fps out of a 20" tube.

On the other hand a short barreled 308 makes a dandy truck gun. If your shooting under 350yds the 308 is all you'll need.

Scott

 

[SJB358]

The 300 RSAUM would probably be a good choice. Better case design for Remington short actions as well. At worst, you would end up with a 30-06 Improved. I think you'll do much better than that actually. The case on the SAUM lends itself to better seating set ups on the 2.8" mag box. Just my opinion though, not saying the WSM wouldn't work just fine either.

Cartridge : .300 Rem SA Ultra Mag
Bullet : .308, 180, Nosler PART SP 16331
Useable Case Capaci: 65.754 grain H2O = 4.269 cm³
Cartridge O.A.L. L6: 2.825 inch = 71.76 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Norma MRP

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 87 54.80 2248 2020 30321 10917 86.5 1.425
-18.0 89 56.17 2312 2137 32536 11335 88.2 1.385
-16.0 91 57.54 2377 2259 34927 11741 89.8 1.345
-14.0 93 58.91 2443 2385 37511 12133 91.3 1.305
-12.0 95 60.28 2509 2516 40307 12509 92.7 1.260
-10.0 97 61.65 2576 2651 43336 12866 94.0 1.217
-08.0 100 63.02 2643 2791 46621 13201 95.2 1.175
-06.0 102 64.39 2710 2935 50189 13513 96.2 1.134
-04.0 104 65.76 2778 3084 54072 13798 97.2 1.095
-02.0 106 67.13 2845 3236 58303 14055 98.0 1.057 ! Near Maximum !
+00.0 108 68.50 2913 3392 62925 14281 98.7 1.021 ! Near Maximum !
+02.0 110 69.87 2981 3553 67981 14474 99.2 0.986 !DANGEROUS LOAD-DO NOT USE!
+04.0 113 71.24 3049 3717 73526 14631 99.6 0.951 !DANGEROUS LOAD-DO NOT USE!
+06.0 115 72.61 3117 3884 79621 14751 99.9 0.918 !DANGEROUS LOAD-DO NOT USE!
+08.0 117 73.98 3185 4055 86340 14831 100.0 0.887 !DANGEROUS LOAD-DO NOT USE!
+10.0 119 75.35 3253 4229 93771 14880 100.0 0.855 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 108 68.50 3071 3771 78393 13841 100.0 0.934 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 108 68.50 2694 2900 49869 13761 91.7 1.133


Cartridge : .300 Rem SA Ultra Mag
Bullet : .308, 180, Nosler PART SP 16331
Useable Case Capaci: 65.754 grain H2O = 4.269 cm³
Cartridge O.A.L. L6: 2.825 inch = 71.76 mm
Barrel Length : 20.0 inch = 508.0 mm
Powder : Hodgdon H414

Predicted data by increasing and decreasing the given charge,
incremented in steps of 2.0% of nominal charge.
CAUTION: Figures exceed maximum and minimum recommended loads !

Step Fill. Charge Vel. Energy Pmax Pmuz Prop.Burnt B_Time
% % Grains fps ft.lbs psi psi % ms

-20.0 77 49.60 2268 2056 33103 10251 89.7 1.390
-18.0 79 50.84 2325 2161 35357 10585 91.0 1.352
-16.0 81 52.08 2383 2269 37787 10910 92.2 1.314
-14.0 83 53.32 2440 2380 40376 11224 93.3 1.273
-12.0 85 54.56 2498 2494 43122 11525 94.4 1.233
-10.0 87 55.80 2555 2610 46029 11814 95.3 1.196
-08.0 89 57.04 2613 2729 49126 12087 96.2 1.160
-06.0 91 58.28 2671 2851 52430 12344 97.0 1.125
-04.0 93 59.52 2728 2975 55959 12585 97.7 1.091 ! Near Maximum !
-02.0 95 60.76 2785 3101 59728 12806 98.3 1.059 ! Near Maximum !
+00.0 97 62.00 2843 3230 63758 13008 98.8 1.027 ! Near Maximum !
+02.0 99 63.24 2900 3361 68070 13190 99.2 0.997 !DANGEROUS LOAD-DO NOT USE!
+04.0 101 64.48 2957 3494 72688 13349 99.6 0.968 !DANGEROUS LOAD-DO NOT USE!
+06.0 103 65.72 3013 3629 77641 13486 99.8 0.940 !DANGEROUS LOAD-DO NOT USE!
+08.0 104 66.96 3069 3766 82957 13599 100.0 0.913 !DANGEROUS LOAD-DO NOT USE!
+10.0 106 68.20 3125 3904 88672 13687 100.0 0.886 !DANGEROUS LOAD-DO NOT USE!

Results caused by ± 10% powder lot-to-lot burning rate variation using nominal charge
Data for burning rate increased by 10% relative to nominal value:
+Ba 97 62.00 2969 3524 76201 12651 100.0 0.952 !DANGEROUS LOAD-DO NOT USE!
Data for burning rate decreased by 10% relative to nominal value:
-Ba 97 62.00 2668 2845 51603 12698 93.3 1.126

 

[Anonymous]

I wouldn't be upset with 30-06 performance. The main reason for this is that I have an intermediate length action. I was going for handier than my 300 win mag and more punch than my 308 Win. Maybe a 350 rem mag would be a better option.

I would think that you'd easily get '06 levels of performance with the .300WSM. With light bullets you'd probably do very well indeed with the right powder. I can easily get 3300+ with RL17 out of my 24". With 180s it drops considerably and some '06 loads nearly match mine with a 24" barrel on both.

 

[wildgene]

...the Winchesters have 24" barrels, Brownings & Tikkas come w/ a 23" barrel. If you're bound & determined you need a 20" barrel, the Ruger Compact Magnum would be the most efficient cartridge (some guy spent a whole bunch of time chopping 2" segments off of .300 short mags, .338 Fed, & .338 RCM barrels). I'd probably go w/ a 22-23" barrel, meself...

 

[Mountain Goat]

One question about your action, is it designed to handle a magnum width cartridge? If the feed rails need to be opened up, then you might as well go with a 30-284 or just stick with the 308.

As far as powders go, it is a myth that faster powders perform better in shorter barrels. What ever powder delivers the highest velocity in a 24" will also deliver the highest velocity in a 20" barrel. What is noticeable at times is the muzzle blast from slower powders when compared to quicker powders.

 

[SJB358]

One question about your action, is it designed to handle a magnum width cartridge? If the feed rails need to be opened up, then you might as well go with a 30-284 or just stick with the 308.

As far as powders go, it is a myth that faster powders perform better in shorter barrels. What ever powder delivers the highest velocity in a 24" will also deliver the highest velocity in a 20" barrel. What is noticeable at times is the muzzle blast from slower powders when compared to quicker powders.

I agree a 100% with MG about this. My Newton has been teaching me this. The same powders that produce out of a 26" barrel work the same out of 21.5" barrel.

The 30-284 would be real sweet as well.

 

[Mountain Goat]

You can also do a search for post by user Big Squeeze who did some extensive work with a Ruger Frontier that has a short 16.5" barrel, if I recall correctly. He listed some chrono data inhis posts.

 

[Larry in SD]

I would think all things being equal it would come down to case capacity vs bore capacity. With that said I would have to say that the .300 WSM should loose less velocity per inch of barrel than either the .270 WSM or 7mm WSM.

I fully understand about the allure of a 20" Barreled Bolt Action. I have had a couple Remington Model 700 Short Actions in which I had the barrels shortened to 18 1/2" and 20". Talk about a sweet handling gun.

Larry

 

[gerry]

There is something to be said about well balanced guns with a shorter barrel, they just seem to point well and are lively. As for the 20" 300 WSM while it wouldn't be my first choice in that caliber it will still come in ahead of typical 30-06 velocities so isn't exactly like throwing rocks at something.

Like many of you I was perusing different on line gun stores and websites and saw someone wanting to sell a 270 WSM that they had chopped to 18" :shock: That would definitely be too short but if a guy could get it for a good price it could be a great donor gun.

 

[Guy Miner]

Some of us just don't like a short barreled smallish bore magnum. Those things just don't "go" together in conventional thought.

I like shorter barreled rifles, and I like the .300 WSM, I'm just not sure that 20" barrel and a .300 WSM cartridge make a lot of sense together. Workable? Sure. Optimal? Hmmmmm.

How about forming the WSM case to .338 or .375? There's already dies and info for the .375 WSM wildcat... Now THAT would get my enthusiastic approval!

Guy

 

[Mountain Goat]

Some of us just don't like a short barreled smallish bore magnum. Those things just don't "go" together in conventional thought.

I like shorter barreled rifles, and I like the .300 WSM, I'm just not sure that 20" barrel and a .300 WSM cartridge make a lot of sense together. Workable? Sure. Optimal? Hmmmmm.

How about forming the WSM case to .338 or .375? There's already dies and info for the .375 WSM wildcat... Now THAT would get my enthusiastic approval!

Guy

Or, the 35 Sambar, which is basically a .358 WSM! The 350 Rem Mag as mentioned before is a good one too.

If I were looking at or looking to build a 20" short mag, non wildcat, it would be the 300WSM. The 300SAUM, which I like even better, wouldn't bother me since I have a good supply of brass already. I bet it becomes scarce in the next few years.

 

[CMBTshooter]

Mike I would love a 375 or a .416. I'd like to use something with minimum brass forming. Maybe the 10.57 maverick, launching 400 grain PTs at 2450 would be trouble for anything on the wrong side of that barrel. I wonder if an EOTech or Aimpoint could stand up to the recoil.

 

[CMBTshooter]

After a little bit of reading on the 375 wsm, I came across the 376 Steyr. Seems to be pretty good performance out of a shorter barrel. What are your thoughts on that cartridge?