Just how much will different case mfg impact velocity if all things are equal. Here's one example

[300WSM]

How much will differing case mfg impact velocity?

I did this test with three different case mfg's...

All trimmed to same length!
Bullet seated same depth!
Same powder and exact charge!
Same #41 primer

Shot in random order to further magnify the variances...
As if someone just grabbed miscellaneous brass and loaded up and hunted and or shooting a group...
Significant or insignificant?

Only you the shooter could answer that but I can say 100 fps as a rule of thumb will differ approximately 1"-1.5" for a 30 cal with a 180 gr bullet at 500 yards all things being equal

Where as a 22 cal with a simple 55gr FMJ/BT will see a 2.5"-3" difference at 500 yards all things being equal.

 

[FOTIS]

You're talking different manufacturer (Headstamped) cases?

I did a test yesterday with the 300 Win mag cases.

Hornady cases weighed 240 grains
Norma cases weighed 220 grains
WW nickel cases weighed 235 grains.

Now if we assume all external dimensions are identical (all full sized cases) then that will tell you something about internal capacity.

 

[300WSM]

You're talking different manufacturer (Headstamped) cases?

I did a test yesterday with the 300 Win mag cases.

Hornady cases weighed 240 grains
Norma cases weighed 220 grains
WW nickel cases weighed 235 grains.

Now if we assume all external dimensions are identical (all full sized cases) then that will tell you something about internal capacity.

Yes...different headstamp and yes the point was to show the differing internal space, or lack thereof, between the multiple manufacturers and it's evidentiary impact on the end result.

 

[Charlie-NY]

Notwithstanding a difference in bullet drop; it would be interesting to see what the difference in point-of-impact is at distance. Barrel harmonics should really come into play with a velocity variance that large.

 

[300WSM]

Notwithstanding a difference in bullet drop; it would be interesting to see what the difference in point-of-impact is at distance. Barrel harmonics should really come into play with a velocity variance that large.

Very valid point!!
Absolutely there would be a difference...
Moreover what else happens in that longer flight time versus the faster example.
Short distances the issues are more negligible than not IMO. You'd still be within the kill zone. Shorter distances being 200 and closer.
IMO...300 yards seems to be the marker where things can start getting magnified.
Wind drift can become an issue. Nothing good comes from longer flight time versus shorter flight time all things being equal.

What you suggested can start playing a role too. Perhaps the negative reaction can start happening sooner than 300 yards. It's a very valid point.

 

[Divernhunter]

I found that the Nosler brass gave the slowest FPS. Hornady brass gave the most FPS. and weatherby, win, rem brass was in the middle. The point of impact was 1 inch plus at 100 yards. This was in several different cartridges also. Now I sort my brass as to manufacture and number of times fired.

 

[300WSM]

I found that the Nosler brass gave the slowest FPS. Hornady brass gave the most FPS. and weatherby, win, rem brass was in the middle. The point of impact was 1 inch plus at 100 yards. This was in several different cartridges also. Now I sort my brass as to manufacture and number of times fired.

I tried doing times fired as in keeping track of it but I just don't have the time for that.
I sort by mfg where needed as in precision shooting or hunting...

I do load some "whatever cases " and keep an ammo can filled. Always keep that on hand for the kids or anyone wanting to blast, gong shoot, etc with an AR

 

[300WSM]

The whole thing is pressure.

That's all we're doing here.

Creating an ignition that creates pressure ultimately releasing that pressure via bullet down the barrel.

The different internal case space or lack of creates variables with the pressure all things being equal

 

[300WSM]

I found that the Nosler brass gave the slowest FPS. Hornady brass gave the most FPS. and weatherby, win, rem brass was in the middle. The point of impact was 1 inch plus at 100 yards. This was in several different cartridges also. Now I sort my brass as to manufacture and number of times fired.

Was that across the board or your findings just on one caliber?

 

[FOTIS]

Notwithstanding a difference in bullet drop; it would be interesting to see what the difference in point-of-impact is at distance. Barrel harmonics should really come into play with a velocity variance that large.

Yes sir. Remember these are exiting the barrel at a different time each.

 

[JD338]

Very valid point!!
Absolutely there would be a difference...
Moreover what else happens in that longer flight time versus the faster example.
Short distances the issues are more negligible than not IMO. You'd still be within the kill zone. Shorter distances being 200 and closer.
IMO...300 yards seems to be the marker where things can start getting magnified.
Wind drift can become an issue. Nothing good comes from longer flight time versus shorter flight time all things being equal.

What you suggested can start playing a role too. Perhaps the negative reaction can start happening sooner than 300 yards. It's a very valid point.

400 yards separates the men from the boys.
Wind starts to become more important than drop.

JD338

 

[TXbaldhunter]

The way I check the difference in case volume from different manufactures is,all cases resized,trimmed and primed,fill a case full with a ball powder and compare the fill on each different case.You might find some cases might be able to hold one or two grains more powder.Which brands hold the most?It really depends on the cartridge.My Winchester 30-06 cases hold more than my Remington cases.My Remington 7mag cases hold more than my Winchester so it really depends.

 

[TexasLife]

What was the average/percentage of case fill per different cases? And furthermore, what was the charge based on? Using a known load or something out of a published manual? If you had to guesstimate? Most of my brass over the years have been the same manufacturer per cartridge, so I never checked with my known loads between different batches let alone different years of production. I never had anyone to really teach me enough, only basics of reloading. I'm glad nothing bad happened in the process! With most of me 556 brass being the same mfgr and factory load of the same bullets I probably won't separate (unless it's a different mfgr). My 308win brass is a different story (5 different mfgrs).

 

[300WSM]

What was the average/percentage of case fill per different cases? And furthermore, what was the charge based on? Using a known load or something out of a published manual? If you had to guesstimate? Most of my brass over the years have been the same manufacturer per cartridge, so I never checked with my known loads between different batches let alone different years of production. I never had anyone to really teach me enough, only basics of reloading. I'm glad nothing bad happened in the process! With most of me 556 brass being the same mfgr and factory load of the same bullets I probably won't separate (unless it's a different mfgr). My 308win brass is a different story (5 different mfgrs).

Ramshot published data
Starting load 22.4
Max load 24.9

These were at 24.0 on the button

Percentage filled I've no idea...


The 308...
I have gobs of differing mfg'd cases


But...

I will be testing that next. Just for my own curiosity on the deviation between cases in the 7.62x51

Possibly tomorrow
Rebuilding two Dana 44's for a customer tomorrow so we'll see how much light I've left after

 

[TXbaldhunter]

What was the average/percentage of case fill per different cases? And furthermore, what was the charge based on? Using a known load or something out of a published manual? If you had to guesstimate? Most of my brass over the years have been the same manufacturer per cartridge, so I never checked with my known loads between different batches let alone different years of production. I never had anyone to really teach me enough, only basics of reloading. I'm glad nothing bad happened in the process! With most of me 556 brass being the same mfgr and factory load of the same bullets I probably won't separate (unless it's a different mfgr). My 308win brass is a different story (5 different mfgrs).

Years ago,I bought a 308 Win.I made some test loads with 45.5grs of Varget with 165gr bullets.I had Winchester,Nosler and Remington brass.I didn't have my chronograph with me that day,but the Winchester and Nosler brass loads were shooting the same tight groups around .5".The Remington brass was giving me groups that were almost an inch larger.I never checked out why.At the time I just blamed it on the brass,but more than likely it was due to the difference in case volume.Could be the loads in the Remington cases were running at a higher or lower pressure than the other two brands of cases causing the group size to open up.You really may never notice the difference in case volumes if you powder charges are much less than a compressed load.But when you start getting powder charges that get into the cartridge neck,you really start to notice the difference in case fill.I find it's much better to not mix different brands of brass if your looking for accuracy.Consistency is important if your looking for accuracy.Keep your brass segregated but the number of times fired.I write on ever case,the bullet weight,powder and charge,as well as number of times fired.Also keep track of the length so you know the seating depth.Keep them the same length.Powder can change from lot to lot too,so keep that in mind too.After a few firing,the brass starts getting hard.This can cause the neck tension to get tighter and can change your accuracy too.It's best to anneal after at least by the third firing.Take good notes.I have a small note book I take to the range.Don't rely on your memory,over time you will forget.

 

[TexasLife]

Ramshot published data
Starting load 22.4
Max load 24.9

These were at 24.0 on the button

Percentage filled I've no idea...


The 308...
I have gobs of differing mfg'd cases


But...

I will be testing that next. Just for my own curiosity on the deviation between cases in the 7.62x51

Possibly tomorrow
Rebuilding two Dana 44's for a customer tomorrow so we'll see how much light I've left after

For a Jeep or something else?

 

[300WSM]

For a Jeep or something else?

JK..
Whoever did his R&P swap before he got it didn't set it right thus it's got broken teeth galore.

 

[TackDriver284]

Sticking with one brand / lot of brass puts your mind at ease, one less variable to deal with. I usually buy a lot of 50 or 100 and go shoot. Once I find a good load, and if one or two pieces of brass causes a flier that strays from the group, I would mark it for next time to see if it does it again, if it does, then I use them for fouling shots after cleaning the bore.

 

[Divernhunter]

Was that across the board or your findings just on one caliber?

It was true for 257W, 338win mag, and a couple of others. I just started separating my brass after that and did no more "testing". Knowing tis I was able to get 2 loads with the 257W to shoot to the same POI (within less than a inch at 100 yards) using 100gr TTSX and 120gr Swift A-Frame bullets. Both were fast loads.