16ga.com ~ View topic - 65mm full crimp tested

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

I sent two loads in for testing to Precision Reloading. Figured I would share the results with the group.

BOTH LOADS: Cheddite hulls trimmed to 65mm. Cheddite primers. 1oz load with Win 572. 15/16oz load with Unique. Full 6 point crimp with +/- .050 crimp.

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Load No 1: Winchester 572

Hull: Cheddite 16ga - 65mm
Primer: Cheddite
Powder: 20.0 grains Winchester 572
Wad: SG16
Shot: 435 grains (1 oz) 7 1/2
Crimp: 6 point +/- .050" crimp depth

Velocity Avg: 1227 fps
SD: 11 fps
ES: 35 fps

Pressure Avg: 6,395 psi
SD: 349 psi
EV: 890 psi

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Load No. 2 - Unique - This load requires some special notes. Although it tested with a wide SD/ES I believe the load is much better than those numbers because 1 single off round totally skewed the numbers. I'll post those at the end. Also the results were far higher velocity that I showed in my tests.

Hull: Cheddite 16ga - 65mm
Primer: Cheddite
Powder: 18.0 grains Unique
Wad: SG16S (short wad)
Shot: 410 grains (15/16 oz) 7 1/2
Crimp: 6 point +/- .050" crimp depth

Velocity Avg: 1211 fps
SD: 30 fps
ES: 80 fps

Pressure Avg: 6,728 psi
SD: 301 psi
EV: 840 psi

Special Note if your interested in digging deeper: Shot 2 of this 6 shot string had a wildly different fps that all 5 other shots. Shot 2 was 1151 fps. All 5 other shots between 1207 fps and 1231 fps. I presume there was some issue with this round, or a glitch in the chrono. Shot 2 registered 6,450 psi, well within average for this string. Bad primer? Bad crimp? Short powder drop? Who knows. However without this 1 bad one this string would have had an excellent SD/ES.

Shot 1: 1227 fps
Shot 2: 1151 fps
Shot 3: 1222 fps
Shot 4: 1207 fps
Shot 5: 1231 fps
Shot 6: 1231 fps

I would also note that I tested both of these loads over my ProChronoDLX. Load 1 tested right at 1230 fps, and was just as expected. The Unique load I tested at 1,151 fps, 12 SD, 34 ES. I'm really not sure why the difference. I intend to further test this load as I believe it has potential to be an excellent hand trap and light hunting load.

Have a good one!

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

This is what I know.

If you have a test string and a load does what that load shows, either you assembled that one round incorrectly (nicked a wad skirt, 1 grain too little powder etc) or that load will demonstrate that it is not a good load and the one round that is off will keep reappearing. Please understand this is not a criticism, it is just how things work.

You cannot discount that round as an anomaly. The only thing you can do is reshoot that load using a 10 round string. Ballistics rely on statistics and you can't drop a round or explain it away just because you like the load. Been there, got a 'T' shirt or two to prove it.

An easy way to prove or disprove the load as being good, is to build 10 rounds and run them over a chronograph and see what you get. You know the load is under SAAMI MAP, you are just uncertain that it is consistent. No need to retest if you have a chronograph.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

This is an observation, that most don't want to hear. Powder likes to be worked, 6,700 PSI is not making the powder work. Most powders want chamber pressures 9,000 PSI and up. I know that you probably wanted the low chamber pressure, but sometimes it doesn't work out.

Mark,

I'll first say, as you well know, I'm not an expert on internal ballistics and certainly do not have even the slightest fraction of your shotshell testing experience. For my part I am merely an inveterate "load extrapolater" -- a ballistic sinner if ever there was, and possibly ballistically insane, not to mention ignorant. Such is the modest extent of my enlightenment and current state of illusionment, and I don't recommend anyone should do what I do. But I digress, and will finish by saying I really enjoy your experience-sharing. It can be very enlightening -- to me at least, so thanks.

Now the issue at hand: You used the expression "making the powder work". Your preference for peak pressures greater than 9000 psi is well known to this forum, and I appreciate that. You associate such pressure levels with "making the powder work". I think you mean peak pressures greater than 9000 psi lead to loads making more efficient use of powders, and possibly loads more consistent under a variety of ambient conditions (mostly temperature, I suppose).

Now the questions: 1) Is it reasonable to desire peak pressures of lower levels, considering strength limitations of the firearm in which such cartridges are to be used? i.e. Others may have needs and goals other than those I presume you have. 2) If such desire is reasonable, and cartridges of the desired peak pressure limitation can be made (i.e. demonstrated statistically to stay below certain limits), even though they have less than ideal SD's and EV's (whatever "ideal" is), is that not "making the powder work" for the application?

I'm not trying to get you to say any given peak pressure level is safe for any given barrel. No one can say that, except those who have subjected a given barrel to a level of pressure that indicates some bounds of peak pressures or pressure vs. time or distance down the barrel that will result in safe shooting -- sounds like a proof test, doesn't it. I'd simply like your opinion on the reasonability of efforts to produce cartridges of lower peak pressures that are usefully and safely consistent "enough". My opinion is that proper and reasonable statistical testing should define the risks of loading to lower peak pressures just the same as it does for loads having peak pressures 9000 psi or greater, or any desired limiting level for that matter, and "making the powder work" is a matter of the objective.

Best Wishes,
Tony

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

M73 ... Mark is just telling you where that outlier came from and I don't think that in any way is an anomoly - using Unique for sure ! Unique is a great powder , old . dirty , slow burning etc . What you have is probably a great load for your gun and confidence , just not a great load per definition . I used to use a similar load but with 20grns Unique , and never looked back . (short case and all) . Where I might get a little quesey with your load is in cold weather .... i am going thru a similar program getting 28ga loads to work with Green Dot . Got 3# to use up and the load is now : 11.5GD , Fed case and Chedd primer , and down to 5/8 shot . For the most part , the load is happy . 1100 chucks them out just right , case mouth not stretched - is a nice load but every so often I get a funny sounder . Still cycles etc , but you know it's not quite the same . Use this for skeet only , so not worried if the load sounds off occasionally .

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

Maximumsmoke,

#1, Yes I think it is reasonable to seek loads with chamber pressures lower than 8,000 PSI. However the more the chamber pressure drops the more potential there is for the load not to perform well in all conditions. Or to have individual loads that exhibit velocities that are inconsistent. I personally have chased loads, just like the load using Unique that makintrax73 had tested, only to have an outlier or two mess up an otherwise perfectly nice 10 shot string. Please understand an 11,000 PSI chamber pressure does not automatically mean velocities with low Sd's and EV's, but it sure helps. If I had to come up with a nice load at lower chamber pressures, there would be a CCI209M or a Federal 209A lighting off the mix. The issue with 'low pressure' loads is that the powder isn't consumed in a consistent way, more robust primers can help, but not 100% of the time.

#2, In a perfect load, you want the least amount of powder doing the maximum amount of work. Of course that isn't possible in this scenario. The only thing you can do is to keep trying different component combinations until you get one that works. Usually a primer change solves the issue, at least at 70 degrees F. That would be making the powder work but, not like it should. I believe that progressive burning powders, and that's what we are reloading with, do best when they are used the way the engineers intended. No smokeless powder that I know of was made to work well at 6,000 PSI. If they do, it's a bonus. SR7625 was one powder that you could get to work well in many of these 'low pressure' loads.

Finally, and this is my opinion, If you don't trust a shotgun at 10, 000 PSI why would you put your face on that shotgun with a load at 6,000 PSI? It is also my opinion that when a shotgun does fail, that there is something else going on other than a 10,000 PSI load. The problem is, rarely does a shotgun that failed ever go to an expert that can take x-rays and determine why that shotgun did fail. It ends up being someone's opinion rather than fact.

I can't remember now where I saw this, but a less than decent, older SxS shotgun came apart at the chamber. There were all kinds for opinions on why the shotgun ruptured at the chamber. Turns out that where the rib was soldered at the chamber, rust had formed at the point where that rib met the barrel where it couldn't be seen. That rust created a stress riser and over time the barrel began to crack until eventually the barrel ruptured, starting at the rusted spot.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

makintrax73,

I would have bet that the Winchester 572 load would have given you the outlier rather than the Unique load LOL......so much for SWAG's.

Damn, I like Winchester 572. I am going to try some other loads with it over the next few weeks, I'll post the results.

For the Unique load, if it doesn't work out, just try another primer. Many times that solves the problem.

BTW, what shotgun are you making the loads for?

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

Joined: 27 Oct 2017 Posts: 80 Location: Joliet, IL

Update with re-shoot of the Unique load chrono results 7/26/22:
ProChronoDLX 3' from the muzzle
_____________

Warm up/sanity check with RST falcon lite (1,125 advertised)

1) 1,043 fps
2) 1,108
3) 1,106

______________

10 shot string with my load. Cheddite 65mm, Ched prim, 18.0 Unique, SG16S, 15/16ths No. 7 1/2

1) 1,184 fps
2) 1,150
3) 1,158
4) 1,164
5) 1,166
6) 1,164
7) 1,152
Cool

1,145
9) 1,132
10) 1,145

Avg fps: 1,152 fps
SD: 14 fps
ES: 52 fps

_____________________

Same load, prior session dated 6/27/22

1) 1,132
2) 1,166
3) 1,162
4) 1,146
5) 1,152

Avg fps: 1,151
SD: 12 fps
ES: 34 fps

_______________________

So, the question raised is what went wrong with the load as tested by Precision Reloading. The average velocity is too far divergent to be easily explained.

Since I have a lot of headspace on PSI I may bump the powder charge I may bump it to 18.5 to see if cleans up the ES, which I find a little too much. However "as is" it meets my expectations for a warm weather practice load that is light shooting, and uses components which I have available to me.

Guest

Thanks for posting that, makintrax73. That looks pretty good and one I’d use for a ruffed grouse load for my 5 lb. 12 oz. Brit SxS.

Joined: 07 Jun 2020 Posts: 229

MSM2019, I appreciate your posts and more so your shared loading experience

I accept that modern powders are designed for higher pressure loads in order operate at their highest efficiency.

Modern powders burn more cleanly, the higher pressures is part of the cost, a further byproduct is consistency at that higher pressure

The challenge is not that some vintage guns can’t take 10k PSI. Most could, at least a little, it is that they were designed for a diet of 10k PSI, they were designed for a diet nearer to 8k PSI for normal operation. Loading at 8k and below is feeding them what they were made to shoot. The question is not why would I trust it at 6k, but not 10k. The question is why would I feed it ammo for which it was not designed.

Once you have made the decision to shoot older guns, you have to accept that you have to shoot compatible ammo.

Joined: 04 Mar 2019 Posts: 1844 Location: Central ND

Old colonel2,

Speaking of steel barreled shotguns only. I realize that some Euro/UK shotguns were proofed at lower pressures. After 1926 and even before 1926 many shotguns made here in the US were proofed at levels similar to current standards. The current SAAMI MAP is also close to the same pressure levels that have been used since 1926, when SAAMI Standards were first introduced. As you know SAAMI MAP refers to the maximum service pressure to get the maximum life out of your shotgun.

I guess that a person would have to know, which shotguns were not proofed or designed for those levels. IMHO, I think folks take this way too far and are using 'low pressure' loads when they aren't warranted. Again, just my opinion.

There are plenty of references on 16ga.com to folks 'needing' low pressure loads but the actual shotguns are never mentioned, which I think is a bit curious. Maybe there are a lot of folks that shoot older shotguns that need ammo that isn't up to current standards, more than I think.

There is nothing wrong with using 'low pressure' loads, in whatever shotgun a person wants, it just isn't my choice for the reasons I have stated many times over.

Joined: 16 Jul 2015 Posts: 2126 Location: Hudson,Wy

Thanks for posting this. I have been waiting to see how the 572 load came out since I am wanting to do about the same. That low pressure reading gives me mixed feelings. I would like a bit higher...without the higher velocity so it leaves me pondering things since I find guns usually pattern most efficiently, especially once I get away from light shot charges, at speeds below 1,300 fps.

However, the low pressure situation almost begs for the move to a buffered load that would no doubt raise pressure by 1,500-2,500 psi while staying within the intended working limits of the British SxS I would use it in. Now I may have to compare such a load with the Longshot load I currently use with buffer. Hmmm.

Joined: 16 Jul 2015 Posts: 2126 Location: Hudson,Wy

Mark, I'm with you on "unwarranted" low pressure loads in guns that were made to handle far more. I often read of folks only using low pressure ammo in guns that I know handle modern ammo just fine. But, if the loads are working well for them in said gun, then I see no reason to change...except when they can't get what they want and ordinary loads are safe in the gun of question.