Reloading Manual Muzzle Velocities

[dbarnhart]

Yesterday I was reading a bit about chronographs and a question occurred to me: What do I compare the chronograph's readings to?

I'm sitting here with the Speer #14 Reloading Manual in front of me looking at the .223 Remington reloading data. I don't see any data here about the kind of gun used to obtain the data. I have a carbine with a 16-inch barrel. Though I can'r find anything that tells me so, I'm betting the listed muzzle velocities were produced with a longer barrel. I'm pretty sure that I'll not see the muzzle velocities listed.

How do you start with the muzzle velocities listed in the reloading manual and determine what they *should be* for your rifle?

 

[RandyP]

You shoot your reloads through your chronograph to determine what the velocities ARE for your rifle. What they "should be" is unimportant.

 

[Walkalong]

I'm betting the listed muzzle velocities were produced with a longer barrel.

My Speer # 14 says they used a Ruger M77 Mk II with a 22" barrel. You must have over looked it.

 

[murf]

to find out what the muzzle velocity should be for your rifle, shoot a factory round over the chronograph. the factory round should use the same bullet as your reloaded round to be a valid baseline for comparison.

this baseline velocity is good only in that rifle shooting that particular bullet. but, in general, it will give you an idea how fast your loaded rounds should be going. fwiw

murf

 

[1SOW]

Keep in mind that manufacturers "barrels" for testing pressures and speed are NOT your bbl. If they say 4" or 16" or whatever bbl, it shouldn't be too far off, but it won't be the same.

I've seen pics of a Speer test bbl and it resembled this new Berry's tester:

 

[nickn10]

I'm fortunate in that I have a place to shoot out to 800 yds if needed. Without a chrono I have used the ballistic chart in my Nosler book to estimate velocity by comparing my results to the chart's, ie. if I start out at 3" high at 100 I see what listed velocity most matches my drop at 200- 300 and 400 yds. It gives me a rough approximation but a useful estimate. Of course you must use the same bullet as the chart.

 

[Clark]

I use a chrono for internet bragging.

My 223 has done 4200 fps.
My 223 has done 4100 fps, and the brass lived another day.

 

[nickn10]

Huh???

 

[2zulu1]

Read the article on pages 769-770, this should answer your question.

 

[nickn10]

Read the article on pages 769-770, this should answer your question.

My Nosler guide is #4 only goes to page 722.

 

[Trent]

I've shot .224 40 gr bullets out to 4500 fps before!

But that wasn't in a 5.56 casing!


They also didn't make it to the target. Approx 75 yards out, you'd see a little gray "poof" and they were gone!

 

[Clark]

Trent
I've shot .224 40 gr bullets out to 4500 fps before!

I've been served

 

[MachIVshooter]

Expect your velocities to vary quite a bit from published data. My first batch of 8mm mag 180 gr. loads was tested in the same rifle Sierra used (a 24" Remington 700 BDL), but velocities averaged 165 FPS faster. I've had some come out even faster (like some .25-06 100 gr. loads that were supposed to be 3,300 and came out at a blistering 3,585 avg.) On many occasions, however, the velocities were lower from the same barrel length as listed in the book.

I use a chrono for internet bragging.

My 223 has done 4200 fps.
My 223 has done 4100 fps, and the brass lived another day.

And I thought I loaded hot, with pierced primers to get 3,900 with 40 grainers out of a 24" Howa 1500.

 

[cfullgraf]

How do you start with the muzzle velocities listed in the reloading manual and determine what they *should be* for your rifle?

I like to "calibrate" a new rifle's barrel by shooting some factory loads over the chronograph. Ideally with the same bullet but more frequently with the same weight bullet.

It give me an idea if my reloads run lots faster than the factory, i figure I am in dangerous territory.

Then, as i work up loads in the rifle, I compare them with the published data. If my velocities are lower than the published data, I know I will never match the published data. Conversely, if my velocities are higher, i know I should not try to match the powder charge in the book. (I never go to maximum loads anyway.)

I look at all the other typical indicators of over pressure but add velocity as another data point to consider.

As an example. Sierra Bullets uses a Colt 20" HBAR for testing 223 Remington semi-auto loads. I happen to have a similar Colt and its velocities, for the couple powders that I have used, match Sierra's data pretty well. My Service Rifle match AR rifle, also with a 20" barrel, has velocities 150-200 fps faster than the Colt or Sierra's data with the same loads.

The velocities in the match rifle were higher than I wanted, so I have reduced the powder charge for my match rounds.