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montana_charlie
09-09-2006, 10:17 PM
I finally found some time to do some shooting.
Actually, I am testing to find the best load for a particular bullet, the Paul Jones Creedmoor which drops at 560 grains from my NEI mould.
I am shooting this slug from a .45-90 case in a Pedersoli Sharps rifle. Range was 100 yards.

I loaded these test rounds back in May, and fired them yesterday - temperature 80, humidity 25%. Fired four 'sighters' to get on the paper, and ran one damp patch between shots for the entire session.
I wasn't trying for a 'clean barrel'...just a consistent one.

I suspect that my bullet alloy is softer than it should be. The 'tin' I bought to make up 20-1 alloy turned out to be only 25% tin...so my alloy didn't come out right. Maybe that's why my bullets weigh 560 grains from a mould that's supposed to throw them at 540 grains.
Anyway, I am willing (for now) to blame poor groups, in the stiffer loadings, on 'slumping'...at least until I get my alloy refigured.

All loads had the bullet seated to the same depth of .665" so only the amount of compression changed as the powder was increased. Charges (of GOEX Cartridge) were:

1st group fired - 75 grains - Smallest five shot group, 1 inch high and 3/4 inches wide.
Average velocity, 1187 - std. deviation 14.76

2nd group fired - 79 grains - Loose group 1 inch high and 3 inches wide.
Average velocity, 1183 - std. deviation 8.24

Last group fired - 80 grains - Poorest group 3 inches high by 2 1/2 inches wide.
Average velocity, 1143 - std. deviation 16.24

This was the first time I have ever used a chronograph. I was hoping it would tell me all kinds of 'magical' things. I do find it interesting to know all of those little details within a shot string, but...

Can anyone provide a reason...or a theory...about why
"more powder means slower bullets"?
CM

John Boy
09-09-2006, 11:11 PM
Charlie: Crimp or no crimp?

Dale53
09-09-2006, 11:58 PM
There is optimum powder compression for a proper burn. When you exceed that, it is possible to decrease the burn rate instead of increasing it (kind of like solid fuel and loose powder).

I, when working up a load for a BPCR, increase compression, from zero, by adding more powder in a progressive way. I let the targets dictate when to stop and back up to a "proper" load - the load that shoots best. I have found this VERY effective.

Goex normally requires much more compression than Swiss, in my experience.

Dale53

44man
09-10-2006, 11:55 AM
Black powder does act strange when too much is used. Compression does have a great effect but even in a muzzle loader there is a point of diminishing return. Once the optimum load is reached, then exceeded, the extra weight of the powder added to the boolit or ball slows the velocity plus it can't all burn in the barrel length so it burns in front of the muzzle.
My friend stuffed 84 gr's in a 45-70 case and it was way slower then 65 gr's. If you watch the chrono, as you increase the charge, the amount of velocity increase will get smaller, then start to go backwards. You can watch this without a chrono by seeing groups climb on a target, then start back down. Or is it the other way around? I forget.
He was compressing Pyrocrap in his 45-70 and I watched plugs of it exit the muzzle like flares and burn for some time in the grass. A great way to start forest fires or cook weenies.

montana_charlie
09-10-2006, 12:06 PM
Charlie: Crimp or no crimp?
Bullets are thumb seated, in firm contact with the lands, and not crimped. Where is your train of thought headed?

There is optimum powder compression for a proper burn. When you exceed that, it is possible to decrease the burn rate instead of increasing it (kind of like solid fuel and loose powder).
I understand the concept of 'too much' powder causing reduced muzzle velocity because the excess propellant becomes part of the mass being pushed down the barrel.
And, I can grasp the idea that a charge which is too heavily compressed can have a less efficient burn characteristic.

But 79 and 80 grains in a .45-90 case should still be below those 'maximums'...I would think.

I, when working up a load for a BPCR, increase compression, from zero, by adding more powder in a progressive way. I let the targets dictate when to stop and back up to a "proper" load - the load that shoots best. I have found this VERY effective.
I followed the same route, in 2 grain increments, to reach the 75 grain load - which produces 1 inch groups with this bullet. But, I was hoping (and still am) that I can find an accurate load which will exceed 1200 fps. Seeing MV starting to decrease, beginning at 79 grains of powder, is disappointing.
Guess I need to go back and look again at 77 grains...now that I have the Chrony to tell me what's happening.
CM

martinibelgian
09-10-2006, 02:16 PM
Charlie,

Very weird indeed - FWIW, my 45-70 with a 30" barrel, 520gr bullet will do following:
74grs 1171 fps
76grs 1220 fps
80grs 1258 fps

Normally, a 45-90 should be easily able to get 1250 fps, even get close to 1300 fps with a 540gr bullet. So 1250 should be certainly possible with a 560gr bullet. Maybe you need to try Swiss powder?

Finn45
09-10-2006, 03:21 PM
What kind of chrono set up and conditions?

44man
09-10-2006, 05:16 PM
I read your post again and you never said what powder you are using. I agree that you should not have a fall off until you get over 90 gr's. Seems like you should be able to shoot 92 to 94 gr's.
The wad you are using can make a huge difference if it is too thick. Try a piece of thick paper on the powder instead. Manila envelopes are good.
The primer can cause a lot of trouble too.
We shoot 72 gr's in the 45-70 and some top shooters shoot 74. I use Swiss FFFG and a Fed LP mag primer with a newspaper over primer wad. Play with primers and see what happens.

montana_charlie
09-10-2006, 11:18 PM
Very weird indeed - FWIW, my 45-70 with a 30" barrel, 520gr bullet will do following:
74grs 1171 fps
76grs 1220 fps
80grs 1258 fps
I think I see the problem! All of my powder charges have odd numbered weights.
Yours are all even numbers!

Maybe you need to try Swiss powder?
Nope, sorry. I have 25 pounds of this Cartridge, which is supposed to be a good choice for this caliber. I'm not going to spring for the price of Swiss until it's all gone...or until I give up BPCR and go back to skinning earthworms with a cavalry saber. That's another endeavor which requires some concentration...

What kind of chrono set up and conditions?
A new Chrony F1 sitting fifteen feet in front of the muzzle. Bullets passed within 4 inches (not more) of the sensors.
I had the diffusers on the Chrony because of the clear conditions, and each shot registered without any error messages.

Conditions? I guess you mean weather.
Sunny, dry, 80, and a very light breeze from dead ahead.



I read your post again and you never said what powder you are using. I agree that you should not have a fall off until you get over 90 gr's. Seems like you should be able to shoot 92 to 94 gr's.
I did say that I used GOEX Cartridge, but like you say...it shouldn't really matter.

The wad you are using can make a huge difference if it is too thick. Try a piece of thick paper on the powder instead. Manila envelopes are good.
Wads are .030 veggies, so even Manila wouldn't change the compression much.

The primer can cause a lot of trouble too.
We shoot 72 gr's in the 45-70 and some top shooters shoot 74. I use Swiss FFFG and a Fed LP mag primer with a newspaper over primer wad. Play with primers and see what happens.
I am using CCI 250 primers because I have 1000 of them. I also have a couple of new boxes of Federal 210's I planned to try after finding a good load...just to see what changes.

If you want to tell me that a certain brand...or certain type...of primer can give me erratic groups or velocities, I won't argue with you. But to say that any particular brand will cause velocities to drop as powder charge increases...well...I can't quite see that.
CM

martinibelgian
09-11-2006, 03:30 AM
Charlie,
I would hold off till you have the harder and lighter bullets, to exclude bullet alloy, annd then try again.
Also, next time try shooting your loads in 'reverse order', i.e. from heavy to light, to see if that still produces the same effect (I'm thinking of a gradual fouling accumulation here, slowing down each successive shot). Also, load with a bit more compression, stuff more powder in there (at even numbers :-D )
Try also 2 patches between shots - 1 wet, 1 dry, to get more consistency - depending on barrel temp, the moisture could evaporate when the barrel is hot, creating a different condition for the shots from a hot barrel.
FWIW, between 63 and 70grs, MV gains with my 45-70 are small at best, but as from 76grs, I am experiencing quite a 'jump', as you will have noticed.

However, jufging from your groups, I am inclined to think you will have experienced nose slump with those bullets - a 45-90 does require a somewhat harder alloy, Irun my 45-70 at 20:1, so 30:1 would be a good starting point. Anything softer would get you into trouble, IMO.

44man
09-11-2006, 08:18 AM
The only thing about primers is some powders like Swiss can take a gentle ignition. Other powders need a lot of fire like the LR mag. I only use Federals so I am not going to try and tell you a certain brand is better. I am sure you are fine with what you have.
I went back and did see you mentioned the powder, I must be going blind!
I guess changing the alloy would be my first choice, then go ahead and make a big jump in your charge and see what it does.
I have read where Goex likes a LOT of compression, some guys going over 1/2". I use Swiss because it is easy for me to get at a decent price. It is also fast. I was never able to get the velocity high with the old Goex in my 45-70.
My friend and I went to the paper wad that is .005" thick. We only use it to get the powder compressed. We have shot many times without a wad at all and never found where one was needed. I have a box full of .060" and .030" LDPE wads. The only thing I ever seen was a loss of accuracy in my gun with the .030" wad. I don't know why but my gun shoots better with a piece of paper.

montana_charlie
09-11-2006, 01:15 PM
Charlie,
I would hold off till you have the harder and lighter bullets, to exclude bullet alloy, annd then try again.
Because I have about thirty left, I will go ahead and shoot these 'soft' ones just to see if things remain the same. If they do...I won't bother anybody with the boring details. Besides, I need to use up the SPG in my sizer so I can try some of Bullshop's NASA lube.

Also, next time try shooting your loads in 'reverse order', i.e. from heavy to light, to see if that still produces the same effect (I'm thinking of a gradual fouling accumulation here, slowing down each successive shot).
I had already decided to do that..based on similar reasoning. Besides, going down to progressively lighter loads helps prevent getting 'twitchy' as the session goes on.
On two occasions I touched off the trigger without cocking the hammer. I'm proud to say there was absolutely no flinch...

Also, load with a bit more compression, stuff more powder in there (at even numbers :-D )
Yep. I plan to load up a few cases with 85 grains...even if that knocks me over backward.
(Oops!...that's another odd number...Oh, well...)

Try also 2 patches between shots - 1 wet, 1 dry, to get more consistency - depending on barrel temp, the moisture could evaporate when the barrel is hot, creating a different condition for the shots from a hot barrel.
OK, I will, though I was shooting very slowly to try to keep the barrel at a constant temperature...and running the spit patch at the end of the cooling period.
Actually, I find patching to be a pain in the butt compared to blow tubing.
But tubing takes time away from my cigarette smoking.
(People complain about only having two hands. My problem is only having one mouth!)

However, jufging from your groups, I am inclined to think you will have experienced nose slump with those bullets - a 45-90 does require a somewhat harder alloy, Irun my 45-70 at 20:1, so 30:1 would be a good starting point. Anything softer would get you into trouble, IMO.
30:1 is what I tried to make, but my 'pure tin' was 75% lead. Not real sure what I came out with, but it's 'too soft'. Because of that, I nearly threw away my new Lee hardness tester. It was telling me things that just couldn't be true...but now I know they were.

I do have 300 PGT bullets cast from one of the 'loaner' moulds that went around during that program.
In addition to the 300, I had seven 'rejects' which I loaded up and fired with 77 grains of Cartridge. The group was pretty good, considering.
150 of those are of the 'too soft 30:1 alloy', but the last batch was supposed to be 20:1. I'm sure (now) it doesn't make that ratio, but it might be hard enough to make a difference...especially considering the nose is a bit shorter, and it fits tighter in my lands.
I really hate the thought of melting down the 'soft' ones, as they are irreplaceable...unless I can get a mould made. But, they might be OK for lower powered hunting bullets...

I do appreciate the responses you guys are providing. Even if you suggest something that I had already thought of, the 'confirmation' is worth a lot.

44man,
I will keep your primer suggestions in mind...when I get far enough down a successful path to start trying changes of individual components.

Finn45,
I hope you come back with more on the chronograph setup.
I am new at using one, and if you have some advice I'd be happy to hear it.
CM

Harpman
09-11-2006, 02:23 PM
FWIW....probly not the problem, ...I have gotten as much as 100fps difference, just by not being consistent in swabbing between shots...amount of cleaning mix on cleaning patch, saturated or just damp made a huge difference...speed going through the barrel, how many patches...has to be exact for me to get consistant fps. I got to where now, after the shot just to be consistant, I clean immediately before even looking through the scope, just incase the fowling may get harder and not clean as it would otherwise...starting to think now, if we look at the gun wrong the darn group might open up !

Finn45
09-11-2006, 03:47 PM
Well, I asked because when I have once experienced goofy results for some reason, I normally think that it's possible for others to do the same. But per your description of your set up and weather I don't believe there's problems.

Anyway, what I have found is that Chrony can give wrong readings with certain light conditions. I use Alpha model, which is basically the same as yours. On a cloudy day I don't use diffusers, just those rods to keep me shooting straight over it. This works also in low light... as long as it works. Best conditions in general have been later evening, when sun is behind my range building leaving the Chrony on the shade, but still clear blue sky over it, no need for diffusers or card boards.

If there's any amount of direct sun, I use old or new card board target over the rods to prevent direct light to sensors and the boolit path over the Chrony. Diffusers have never served me well, because sun is always somewhere else than directly above.

Only time with clearly wrong readings (without any error messages) happened few years ago; I was shooting strings increasing the powder charge. Chrono readings were suspiciously low and they stood basically the same and even went slightly to wrong direction string after string. I drove home in the middle of the session to get new battery but that was not the problem. It was late evening, raining slightly and getting to low light and my Chrony was under the range roof over hang because of the rain. Range booth behind me was already very dark and only light came from the front, not from above (as it should) and this was causing erratic readings, but Chrony was still working without error messages. Next day the problem was gone and velocities were as they should. This was serious hot load development, so there really was a big difference from start to finish.

Btw, heavy cardboard piece or light ply wood makes nice shield for the Chrony's front panel, just tape it from the top so it's possible to flip up for reading the data. Normal cardboard target is too weak, two sessions ago a 0.04" card wad punched through it leaving nice clean hole. It missed the Chrony front panel though.

Oh yes, remember to check that Chrony is fully opened every time and next time take some other rifle (-s) and loads with you to check it with that as well.

montana_charlie
09-11-2006, 06:42 PM
Best conditions in general have been later evening, when sun is behind my range building leaving the Chrony on the shade, but still clear blue sky over it, no need for diffusers or card boards.
Well, I can't duplicate that. I have to use my spotting scope to see the nearest building...and the closest tree is a mile away. No shade for me...or Chrony.

If there's any amount of direct sun, I use old or new card board target over the rods to prevent direct light to sensors and the boolit path over the Chrony. Diffusers have never served me well, because sun is always somewhere else than directly above.
That might be useful information in trying to explain my observed results. It rather resembles conditions (sun direction and angle) when I was shooting.


Thanks for coming back, Finn45. There were several tidbits in your post (besides those I responded to) that I will remember when I get confusing results.
CM

montana_charlie
09-21-2006, 12:56 PM
Can anyone provide a reason...or a theory...about why
"more powder means slower bullets"?
CM
Fired my next batch of .45-90 test ammo the other day to see if Chrony results differed from that first goofy set.
Powder charges were 75, 77, and 79 grains of Cartridge...and the average velocity for each 5-round group went up a few fps with each increase in powder.

It was another blue-sky day, and the sun angle was about the same as before.
If I did anything differently from the first try, it was cranking the Chrony tripod up an inch or two...which made the bullets pass closer to the sensors. Maybe that was the deal...

Groups were kinda crappy, but I'm still shooting those 'too soft' bullets. I'll get some fresh alloy mixed up when all of my lead gets here. Redneckdan is having a heck of a time getting it to me through USPS. One 65-pound box is still 'floating around' (how's that for a euphemism?) out there, somewhere.

I would like to get above 1200 fps, and none of those loads will quite do that with my 560 gr. bullet. But, that 77gr. charge sure is 'consistent'. It produced an SD of only 3.00.

Next time out will be 79, 82...and 85 grains, if that much compression doesn't swell the case.
CM

martinibelgian
09-21-2006, 04:41 PM
CM,
You should really get above 1200 with a 45-90 - and remember, you need small SD's that go hand in hand with good accuracy. Small SD's and bad accuracy don't mean sh*t. let's see how those higher loads perform...

powderburnerr
09-21-2006, 08:20 PM
What brand cases are you using ? that makes a difference ..in starline cases 73 gns will do over 1200 . if you are using win stretched 45-70 you probably need more powder . compression between 25 and 35 after drop tubing is where i get good results...... remember that long cases handle more compression . dean

montana_charlie
09-21-2006, 11:11 PM
What brand cases are you using ?
Bell brass...matched by weight

compression between 25 and 35 after drop tubing is where i get good results.
I just finished making the next batch of test loads.
As it happened, I chose this reloading session to start recording the actual amount of compression needed to get the top of the wad down to .675" below the case mouth. That's the depth my bullet needs.

After drop tubing, 79 grains of powder needed .265", 82 grains went .330", and 85 grains required .390".

Even that much packing down did not swell the case, so I'm satisfied that these are 'reasonable' loads.
My supply is dwindling, but these are some of those 'too soft' bullets. So, I won't be surprised if the groups are ragged. Just need a calm day to try them out...

If none of these get over 1200 fps, I'm gonna try fertilizer and diesel fuel.
CM