Muzzle velocity

[samrobles512]

Hello,
I am very new to this and trying to figure out what my muzzle velocity is for my Tikka T3x lite chambered in 300 win mag. The bullet I am using is the Hornady Eld-X 178. The Tikka has a 24 3/8" barrel and the barrel Hornady uses for testing is 26" and on their website they say that barrel has a muzzle velocity of 2960. I don't have any fancy tools to figure out the muzzle velocity of my gun so I was wondering if somebody already has this information or has an easy way of figuring it out. Thank you.

 

[jimbires]

I played with quickload and got it set to show a 26" bbl would give 2959 FPS with a 178 ELD-X . then I changed ONLY the BBL length , to 24.375" . the program now shows 2912 FPS . this should be a pretty close guess .

 

[memtb]

jimbires is probably close, but....it is a guess. Different barrels of the same length often show a fairly wide velocity range with identical loads. For anything other than long range shooting....it should be "close enough for government work"! memtb

 

[DocDoc]

Roughly 20-30 FPS for each inch. Less for larger calibers. For all, you neeed to shoot at different ranges to get the "dope" on your system.

 

[Blacktailer]

At today's prices you should get a chronograph, then you will know. My brother and I split an Oehler back in the mid 80's when the cost of a good chronograph was equal to about 2 good rifles. Best investment I ever made. Today you can pick up one of the less expensive chronographs for half the cost of a good rifle. If you are going to reload there is no excuse to not have one.

 

[WildBillG]

Your best way to have a rough idea will be the range. It will need to likely have a distance of 700 or more yards. then go by the chart on the box and start shooting moving out as you shoot. you will soon know if your velocity is higher or lower. A Hornady ballistic calculator avlible on their web site should help you find your velocity or close to it. It is impossible to guess what velocity a rifle will give you.

 

[FEENIX]

Hello,
I am very new to this and trying to figure out what my muzzle velocity is for my Tikka T3x lite chambered in 300 win mag. The bullet I am using is the Hornady Eld-X 178. The Tikka has a 24 3/8" barrel and the barrel Hornady uses for testing is 26" and on their website they say that barrel has a muzzle velocity of 2960. I don't have any fancy tools to figure out the muzzle velocity of my gun so I was wondering if somebody already has this information or has an easy way of figuring it out. Thank you.

Welcome to LRH and enjoy it! Sometimes WAGs are not good enough. As others noted, it is best to chronograph your "actual" MV out of your rifle. For instance, I was doing load development for my .30 Gibbs using H4831SC and 190 Berger. Berger reloading manual shows 2671 FPS MV with 57.5 H4831SC out of 26" 1:12" for .30-06. My actual MV with 61 H4831SC out of 1:10" 24" is only 2599 FPS MV.

I was expecting ~50-75 FPS slower for the same powder charge but not with +3.5g.

Good luck!

ADDED: 09/13/20

For what it is worth ...

 

[vancewalker007]

Hello,
I am very new to this and trying to figure out what my muzzle velocity is for my Tikka T3x lite chambered in 300 win mag. The bullet I am using is the Hornady Eld-X 178. The Tikka has a 24 3/8" barrel and the barrel Hornady uses for testing is 26" and on their website they say that barrel has a muzzle velocity of 2960. I don't have any fancy tools to figure out the muzzle velocity of my gun so I was wondering if somebody already has this information or has an easy way of figuring it out. Thank you.

Find a friend with a magneto speed and you'll be on good shape. You can't really estimate this stuff accurately. Even when you use a chrono you still gotta shoot it at distance to verify your numbers, if you intend to shoot very far.

 

[rammac]

That video is poorly done, it states that you are finding the true muzzle velocity but you are actually adjusting the muzzle velocity in the ballistics software to match up with the drop at the target, that's called "truing" the software and it can produce muzzle velocity numbers that are way off of the true value.

While the muzzle velocity is the main factor that effects bullet velocity at short ranges (300 yards or less) the BC value also has an effect and will create some errors in estimating the muzzle velocity. I've had bullets that required a trued muzzle velocity of a couple hundred feet per second higher than my actual muzzle velocity based on the impacts on a 400 yard target.

You really need a chronograph in order to know what your true muzzle velocity is. But don't forget that you need to true your ballistics software for real field conditions.

 

[yorke-1]

I've actually had good luck calculating muzzle velocity from bullet drops if you have an accurate gun/load using a reliable ballistics program and a bullet with a well established BC. Just get a very accurate 100 yard zero and then work your way out to the farthest range you can shoot at paper targets.

Here's an example:

338 CheyTac pistol with a 20" barrel and a 1.3" muzzle diameter with a massive muzzle brake, so the Magneto chronograph won't work on there (I'm too cheap to buy the adapters to make it work! LOL). I'm shooting the 300gr Berger OTM which has a well established G7 BC of roughly .420-.421, I always use .420 and get excellent results out to 2000 yards. I zeroed the gun at exactly 100 yards from the muzzle, verified with an accurate range finder (Terrapin in this case). The groups are .3 MOA for 3 shots out to 600 yards, so I can be confident that my shots land where I want them too out to that range. With a solid 100 yard zero, I move out to 300 yards and shoot at a tall target with a .5 MOA point of aim and fire a 3 shot group. and measure the bullet drop. I'm not making any adjustments to my zero, just letting the bullet impact bellow the point of aim. I'll repeat this 3 times with 3 different aiming points. From there I'll move out to a greater distance and repeat the same process, shooting at a .5 MOA POA and measuring the bullet drop for 3 different groups. I'll repeat this process out to the max range that I can set up a paper target.

From there I get home and measure my bullet drops on the targets and get the average bullet drop at each range. Take that information and plug it into a reliable ballistics program like JBM, using a well established BC (in my case it was a .420 G7 for the 300gr OTM) and make adjustments to the velocity in the program until you actual data matches up closely with the data generated by the ballistics program. For me, I ended up with a muzzle velocity of 2875 fps. I then took that velocity, plugged it into a ballistic calculator and took a few shots at 1500 yards. I was within .2 MIL on target using that data, so from there it was very easy to adjust the numbers to match up with the real world data I had.

It takes a little time, but I thought it was a fun process. It's a lot easier to just borrow a chronograph though!

 

[Tulsa Reiner]

At today's prices you should get a chronograph, then you will know. My brother and I split an Oehler back in the mid 80's when the cost of a good chronograph was equal to about 2 good rifles. Best investment I ever made. Today you can pick up one of the less expensive chronographs for half the cost of a good rifle. If you are going to reload there is no excuse to not have one.

Alternatively, ask around at the range or among some hunting friends. You are bound to find someone who has a good chronograph that they will set up for you to measure your muzzle velocities. Shoot a minimum of 5 rounds, and preferably 10, to get your best average. Also, beware that different factory ammo for the same cartridge will yield different MV's out of your rifle. You cannot even go by the MV published on the box of most modern good quality ammo.

 

[FEENIX]

That video is poorly done, it states that you are finding the true muzzle velocity but you are actually adjusting the muzzle velocity in the ballistics software to match up with the drop at the target, that's called "truing" the software and it can produce muzzle velocity numbers that are way off of the true value.

While the muzzle velocity is the main factor that effects bullet velocity at short ranges (300 yards or less) the BC value also has an effect and will create some errors in estimating the muzzle velocity. I've had bullets that required a trued muzzle velocity of a couple hundred feet per second higher than my actual muzzle velocity based on the impacts on a 400 yard target.

You really need a chronograph in order to know what your true muzzle velocity is. But don't forget that you need to true your ballistics software for real field conditions.

I think the need for a chronograph has been well established. Yes, muzzle velocity is the primary factor that "affect" bullet's velocity at various ranges. The video is simply stating instead of taking what's on the ammo box, you can validate it by augmenting it with ballistic apps and "actual" drop at certain distances. That is why I also caveat it as "for what it is worth". I know lots of folks that rely heavily on what is on the box and does no validation like most of us.

 

[JohnCZ]

Chronographs are cheap and most are reasonably accurate, I have seen the same makers barrels, same lengths shoot remarkably different velocities. If you are shooting and loading any magnum 30 cal you can probably afford a chronograph and then you won't have to worry about guessing.