BH209 Lot to lot velocity test

[ENCORE50A]

After taking a mid-morning nap I thought it might be time to do a little testing of BH and with different lot numbers. I currently have three different lots.

Rifle: DUNAMIS 45cal custom

Lots: Lot#37, Lot#39, Lot#41

Bullets: Fury 275gr ST2. Bullets were weighed and matched at 274.6grs each. Bullets were sized to load in a FOULED barrel at 18#.

BH209: The charge was 84grs by WEIGHT. Weight was verified 3 different times.

Wads: A .060" veggie wad was used.

Force: The Wagner force gauge was used to seat each bullet identically the same. Bullet seating force was 40#.

Barrel: The barrel was fouled with 5 rounds prior to testing. The barrel WAS NOT swabbed between shots.

Chrono: All shots fired over a Magnetospeed V3

Weather: Temp 79° overcast.

Every possible bit of care was taken to keep each process of loading identical, or as identical as humanly possible. Bullets... identical weights. Charge.. identical weight verified 3 times on electronic scales. Bullet seating force identical as measured with force gauge.

The results are quite surprising! Who'd have guessed?

 

[phalanx]

Thanks for doing these tests! Quite informative and surprising to me.
John

 

[txhunter58]

The most amazing data you supplied:

Temp was 79 degrees! . It starts off that warm at sunup here! Gonna be 104 today. Makes it hard to shoot unless you start at the crack of dawn

Thanks for the data. Small sample size but #39 was the most consistent. Since I have 4 bottles of 41, good info to have.

 

[HC]

Myth busted……lot 41 isn’t slower than previous lots.

 

[ENCORE50A]

Myth busted……lot 41 isn’t slower than previous lots.

I said the results would be surprising

I can't get a test any more controlled than that.

 

[ElDiablo]

Interesting. I wonder if the results would remain the same with a larger sample size.

 

[ENCORE50A]

Interesting. I wonder if the results would remain the same with a larger sample size.

IMO, other than burning up more propellant, the results likely wouldn't change anything significant.
Maybe....... only a couple fps change in averages.

The reason IMO, that's a pretty controlled test process.
Bullets weighed and matched to the 10th grain. Identical bullet loading force. 3 times verified 84gr weighed charge. All bullets seated to identical forces.

 

[HC]

If….the tests had been performed with equal volume measured charges, then (IMHO) there would have been significant difference’s in velocity and ES between the different lots.

 

[toytruck]

Forgive my ignorance...what is SD and ES?

 

[deerlessbob]

Good and interesting report. Thanks.

 

[brad502a]

Forgive my ignorance...what is SD and ES?

SD standard deviation of the group of shots for velocity, ES extreme spread of velocity

 

[toytruck]

SD standard deviation of the group of shots for velocity, ES extreme spread of velocity

Thank you!

 

[CatamountRob]

If….the tests had been performed with equal volume measured charges, then (IMHO) there would have been significant difference’s in velocity and ES between the different lots.

It would be interesting to find out if that’s actually the case.

 

[ElDiablo]

Yes, the volume-constant lot testing would be great to see!

 

[sabotloader]

But, I would think it would be difficult to get equal volume measurements using the current volume measures. I highly doubt you could/would stay consistent from pour to pour. Weight on the other hand is a positive measure of the actual weight and would include the measurements of the different sizes of granules and fines in the powder.

And since I am not a target shooter I do use volume 95% of the time! I really do not care if I am off 2-3-4 grains in any one load.

Another factor to consider how many volume measures are the same as others. All of us are using the various volume measure could actually be getting different amount of volume.

 

[ElDiablo]

The point would be to attempt to determine if there is a significant difference in velocities between lots using the method the majority of us use to measure charges (by volume).

We know that BH209 particle size has been changing and/or getting denser per unit of volume. It seems that Encore has established with this test that the weight of the powder charge relates directly to velocity. It would follow that, for example, 120 grains by volume of various lots would produce different charge weights and thus different velocities. But I haven’t seen anyone actually test this.

I think the best next test protocol would be to weigh and average 10 volume-measured charges per lot and then use that weight for each lot to conduct the velocity testing.

It’s worth remembering that with BH209 there is no real variance in grain size within a given bottle (fines) like there is other subs. Differences in measures and measuring techniques is of course a reality but wouldn’t factor into this test. We’re just looking to determine how much velocity difference one might expect with a given volume-measured charge between lots with all else being equal.

 

[ENCORE50A]

Okeydokey boys............

Using the identical processes but averaging 10 by VOLUME, I have the following 120grs VOLUME to weight ratios. I used the same volume measure I always use, set at 120grs.

Lot 37............... average weight is 94.7grs

Lot 39............... average weight is 96.1grs

Lot 41............... average weight is 96.2grs.

I'll repeat shooting also but, it might be a day or so. Doc appointment today with the upcoming knee replacement on the 28th.

I'll foul the same, everything will be identical, including seating force, bullets, primers, etc. But again, not a large number. This testing is too precise to just waste primers, BH and bullets for no significant changes.

If one just looks at these numbers, one would think that lots 39 and 41 should be identical in velocity???????
Lot 37 appears that there should be a substantial drop in velocity??????

What's your guess???

 

[michiganmuzzy]

By volume test probably will show more variations for all the same reasons that lead most accuracy chasers to weigh their charges. I wouldn't mind seeing 10 shot strings but i think, like Encore50 says, we can see where that is going from the test he's already done. For most of us “by volume” shooters that don't shoot long range(<300) i think even lot 37 will perform well enough that we barely notice a dif.

 

[ElDiablo]

Thanks Encore for testing this! On paper……with a 1.5 grain difference in weight, the shots from lot 37 ought to average about 60 fps slower. Which is really not enough to notice on paper and may or may not be evident on the chrono.

 

[ENCORE50A]

Ok boys and girls.............
Ol'Encore figured I better finish up this testing before an over abundance of doctor visits and surgery prevents it.

As requested............. I used 120grs VOLUME and measured out 10 of each lot number, weighed them and then took the average weight of each.
All earlier procedures were followed, so no need to repeat them here.
I will though point out that the 275gr Fury ST2 were used again.

Here's the data. NOTE: DON'T USE THE DATA I LISTED BELOW IT IN RED. MY RIFLE IS CUSTOM AND CAPABLE OF HEAVY CHARGES OF BH209. IT WAS ALSO A 300GR XLD




REMEMBER.... THE DATA BELOW WAS 84GRS WEIGHT