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.300 Win Mag out of 20" Barrels

49K views 53 replies 22 participants last post by  hillestadj  
#1 ·
Just wondering if anyone has any "real world" experience with the .300 Win Mag out of a 20" tube in regards to fps. We've all seen the 50-75 fps per inch of barrel lost, but has any one chrono'ed this or have any hard velocity figures?

I've got a line on a .300 Win with a 20" barrel but Im not sure it will give any better performance than a .30-06 which I've already got.

Thanks
 
#2 ·
While it should give you more than a 20" .30-06, the whole reason for the .300 Magnums of any stripe is to do things that only a 24" barrel can accomplish with all that powder. Without the length you will just have a very loud mouthed .30-06.

I have never chronographed a 20" .300, so that is all just my opinion in a way, but ...... I'm just sayin'.
 
#3 ·
It's science...not real-world experience. The 300WM has a high case capacity which allows it to hold/burn more powder, creating pressure for a greater length of time. None of which is of any value if the barrel corking all that pressure is too short to realize its full potential. Magnum rifles give a modicum of improved performance, but it absolutely requires each of the components to be in place or what you wind up with is the performance of a "lesser" cartridge. Buy a 26 inch-barreled 300 WM and then load a reduced charge in the case, topped off with cream o' wheat. Now you have a 30-40 Krag. Or, buy a 300RUM with a 20" barrel and call it a 300WM?

Or, look at it the other way: Buy the gun and tell yourself it's a souped up 308 Winchester! It's all just a matter of perspective, anyway.
 
#7 ·
I know that a .300 WM shines with the 26" barrel. My interest in this gun with the 20" barrel is in its handling. I dont hunt fields or open spaces and alot of it is on foot pushing deer so a long barrel is like weilding a 2x4. That said, the maybe, someday, possibly I'll have a shot at X yards and the extra wallop will come in handy. We all know how that goes.

I am more curious if anyone has real velocity numbers for me so I can decide if this will just be a glorified -06 so to speak.

Perhaps maybe deep down I'm just looking for a way to justify a new gun:rolleyes::).....
 
#52 ·
20 inch barrel



I can understand the need for a new gun :rolleyes: , BUT, even a 30-06 is handicapped with a 20" barrel. That is entering 308 Winchester territory, which is far more efficient in that short of a barrel than either the 300, or the 30-06.
 
#8 ·
It'll be loud. Having said that, I understand your motivation. For hunting from fixed blinds, and "pest control" out the window of a pickup truck :D I was amazed how much handier a 22" barrel was than a 24." Eventually, for quick handling in close quarters, I dropped down to a 20" barreled Marlin and can say it's the best thing I have for getting a shot out the driver's side window in a hurry :eek:

(Yeah I know :rolleyes: but we need pigs to be dead, more than we need the shot to be sporting).

I'm a believer in making the rifle fit the way you want it, and worry about the velocity or inch-lbs. or whatever, later.

Good luck.
 
#9 ·
The following calculations were done using QuickLoad, so they are only highly educated guesses. Your results will not be exactly the same, but they will follow the general patten shown below.

When filling a 300WM with 4831 under a 180gr bullet, one might expect to lose roughly 200fps. This load will give ~3080 from a 26" barrel, down to 2875fps from a barrel that is 20 inches long. (Note that the typical velocity loss of 25fps is exceeded, due to the nature of a magnum cartridge needing a longer barrel to do its job.)

A 30-'06 loaded with a full case of 4350 under the same bullet, shot from a 24" barrel, gives 2825fps. The same load from a 20" barrel clocks in right around 2700fps. I chose these lengths as being realistic, given the cartridge in question. A 24" barrel on an '06 is approximately 50fps slower than a 300WM, with a 20" barrel. Keep in mind you will need 20 more grains of powder and need to deal with tremendous muzzle blast and flash, in doing so.

A magnum rifle with a 20" barrel is like a big-block V8 with a computer shutting off half of the cylinders. Difference is, the engine will provide you with the extra power when you need it, whereas the rifle is permanently handicapped from providing its intended level of performance. My advice is to pass on it unless you really just wanted an '06, anyway.
 
#10 ·
Thanks broom_jm, that the kind of data I was looking for.

I know the muzzle flash may be excessive and the ballistics may be compromised, but I think Im willing to give up a little to gain a lot in the handling department.
 
#11 ·
Just to follow up on this thread, I bought the gun this morning which was posted on gunbroker. Its a NIB Browning Acera battue in .300 WM in case anyone is curious, and Im having trouble wiping the smile off my face from the price I got it at! She should go nicle with the .30-06 Acera I've already got.
 
#12 ·
I don't think it will be that bad. I assume you'll be wearing hearing protection except for a few shots at live game. I live in Pennsylvania where it seems half the hunters use Remington pumps and tons of them are 18.5" 30-06's. I shot one once and itreally didn't seem much different than a 22" gun.
 
#13 ·
I dont think the rifle will be a favorite at the bench...my -06 Acera with 22" barrel weighs about 7 pounds scoped. This 300 WM will remain open sighted at about 6.5 lb and from the looks of the picture the recoil pad is about 1/4" thick or may even by just a hard buttplate. Oh well, I bought the gun to hunt with and I wont feel the recoil at all in the woods.
 
#15 ·
If there was ever a need for a muzzle-brake, this is it !!! Don't forget those shooting muffs !!! It would make a great bear rifle. Load it up with heavy bullets and put a good low-power scope on it. Heavyweight .30 cal. bullets are fairly long and should penetrate well. HD1
 
#16 ·
Why do you say that? It's only going to kick like an '06, especially if he handloads it with a slightly faster powder and a smaller charge that will burn more completely, in the shorter barrel. Adding a brake to this gun is totally unnecessary and will just make a LOUD gun LOUDER! Your advice on heavy bullets is good, but combine that with somewhat reduced charges of faster burning powder and it won't make any more noise than a 20" 30-'06 rifle. The irony is that it won't have any more range than an '06 either, despite what's stamped on the barrel.
 
#18 ·
In my eyes, to cut the barrel of a .300 Win mag down some 6 inches is not in the best interest of the hunter nor the rifle. If velocity is not that important, then get yourself a 45/70 or 444 lever gun and hack the barrel down a few inches. You will be shooting a lot more bullet weight and also much bigger wound channel up close. Just my 2 cents worth!:rolleyes:
 
#19 ·
If you want a short rifle, get a single-shot breech loader. My T/C Encore PH with a 28" barrel on it is an inch shorter than my Browning A-Bolt .30-06. With my 24" .260 barrel, it handles very well in a tree stand while still having a 'full length' barrel. Obviously, you can drop down to a 20" barrel and it should be very short.
 
#20 ·
Ok, if you are not goint to shoot a deer over 100 yards with this 20" barrel 300 Win mag. Whats the point of having the magnum? If you want a short barrel magnum. Go with a 375 Ruger or a Guide gun.

If it is stopping power you want inside of a 100 yards, there are lots of choices out there for that.
 
#21 ·
Actually BROOM_JM, when referring to the need for a muzzle brake, I did so in jest. I do though feel that there is "Felt" recoil as well as "Perceived" recoil. Perceived recoil being due to noise and muzzle jump. A shorter barrel always seems to be louder in my experience and that raises the level of perceived recoil. Handloads could certainly change that, but I guess I wasn't thinking about handloads when I posted. Good shooting...HD1
 
#22 ·
HD1,

That's the problem...we don't have a sarcasm font! :)

I agree that LOUD guns convince you that they kick more, but sometimes those short guns just don't weigh very much, so that extra noise really does come with more recoil. I think the OP is entitled to shoot whatever he wants and don't mean to disparage a decision any fellow shooter/hunter makes. For my personal interests, I like a magnum to have a longer barrel for the added weight and to put the BOOM a few inches further away from my head.
 
#23 ·
I think you will be fine with it. I wouldn't want a 20" barreled 300WM, but in reality, you will get more than a 30-06 out of it, and you will have a great handling rifle. Muzzle flash will probably be brisk, but so is a 44 Rem Mag with a full load of H110 over 250gr bullets. If you are happy with the rifle, and you shoot it well, I can't see any negatives. Have fun with it and let us know how it shoots. 300WM is one of my favorites. Check out some of the 220gr loadings, should make a helluva woods rifle with plenty of legs for a 300 yard shot. Scotty
 
#24 ·
Perhaps the reason behind me purchasing the rifle wasnt made clear since my original question just asked about the ballistics out of a 20" barreled .300WM. I will clear this up for you guys.

I did not wake up one day and say "Self, I think you need a .300WM, and while you're at it why not find one with a 20" barrel". Believe me, I know there are better choices to run out of a 20" barrel, I know breech loaders allow a longer barrel length while maintaining the same overall rifle length, I know there are calibers that pack more whalop, I am well versed in the more traditional "brush guns",etc....I know I know:):)

For lack of a better term I stumbled upon a Browning Acera battue chambered in .300WM on gunbroker and decided if the price was right I should probably have it. This particular battue style came from the factory w/ a 20" tube and open sights since it is a gun designed for the European market where driven hunts with shots at moving game are the norm and a light, short gun is very condusive to that hunting style. Things worked out, the gun is on the way, I am happy with it. Those of you who are familiar with an Acera (probably very few) will know that choice in chamberings is limited :rolleyes:(choice being a poor term since they are fairly few and far between in the states so you get what you get).

Overall, I purchased this rifle because of its model, not what it was chambered in. I am inclined to agree with beretz that it will not give full throttle 300WM ballistics, but will be elevated from the -06 level. I'll report what I find after I take it to the range for the first time.
 
#25 ·
Plus, if you absolutely do not like it, it is only a rebarrel away from having a longer tube! Good luck with it, I bet it will work out fine, and it sounds like a very nice rifle. Some folks shoot 30-06's in pistols. Same principle really. I don't see any real downside other than some muzzle flash. It is still going to shoot flat and hit harder than an 30-06, whats not to like? Scotty
 
#26 ·
Yup. And I think you can get a .300 Win Mag in an Encore, so at 15 inches of barrel.... the fireballs ought to be spectacular :eek: That, alone, should make a 20" rifle barrel seem downright practical!

Point is, those who say "it can't be done" or "it shouldn't be done" or "it will never sell" sometimes over look those who already did it, and the companies who are already selling lots of the same ;)

I wish you luck with it.....
 
#30 ·
Perhaps the reason behind me purchasing the rifle wasnt made clear since my original question just asked about the ballistics out of a 20" barreled .300WM. I will clear this up for you guys.....Overall, I purchased this rifle because of its model, not what it was chambered in. I am inclined to agree with beretz that it will not give full throttle 300WM ballistics, but will be elevated from the -06 level. I'll report what I find after I take it to the range for the first time.
The OP has discovered that there is an awfull lot of opinion and passion on this subject, but darn little fact. Actually I've seen no facts at all answering the OP's initial post. How about some facts?

Rifleshooter Magazine, September 2003:
.300 Winchester Magnum, 180-grain bullet, RL-22
Same barrel used, cut off in increments shown

Barrel...Velocity
27"........3055
26"........3031
25"........3024
24"........3003
23"........2984
22"........2960

Even though the shortest barrel is 22", you get the idea. The .300 WM is still far more powerful than a .30-06 in the same short barrel length. It was well-proven decades ago by dozens of IHMSA shooters that the fastest velocity in a short barrel uses the same powder that gives highest velocities in a long barrel. From the source above:

.300 Remington Ultra Magnum, 220-grain bullet, 22" barrel, max loads
Powder....Velocity
H4895......2612
H-870......2997


Some may say that short barrels are still no good for very large capacity cases. More data from the source above:

.300 Remington Ultra Magnum, 220-grain bullet, H-870
Barrel....Velocity
27"........3107
26"........3088
25"........3062
24"........3046
23"........3018
22"........2997

Please show me a .30-06 which will launch a 220-grain bullet at 3000 fps from a 22" barrel. Please.

I'm certain that the OP will enjoy his new rifle in spite of all the negative opinions posted in this thread. I wish him well and am looking forward to his future reports....if he bothers to post them. Considering the mauling he got in this thread, I wouldn't blame him if he just kept quiet.


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