CoalTrain49
Member
I think SAMMI has chamber specs all the way from the breech face to the rifling.
handload vs factory
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I think SAMMI has chamber specs all the way from the breech face to the rifling.
rfwobbly
Member
SAAMI does list bore and groove diameter, but no dimension on where the rifling starts.
Over pressure can expand the web a hair, just enough to be tight in a small chamber. Sizers can't get down that far. Roll sizing can fix the cases, but most folks do need or aren't going to pony up for one.
rfwobbly
Member
I'd answer this way....
Yes, you're correct. Due to the requirement to hold the case in the shell holder, the sizing die simply can't get down far enough. Plus, with the advent of progressive presses, which find their main use on pistol ammo, die makers had to add a slight lead-in funnel to the sizing die to allow the case to enter the die easily. Adding this funnel reduced the length of case sizing even more.
Now with most pistol cases (45ACP, 40 S&W, 38 Super) you could use a 'bulge buster' type die, where the brass is pushed all the way through the die and even the base is re-sized. But you have forgotten one very important point...
The 9mm series (9x19, 9x21, 9x23, etc) of cartridges DO NOT use true straight-walled cases. We lump them with "straight walled" for the sake of discussion, but they are actually tapered cases. And it's that tapered external shape which limits so much of what we can do with 9mm brass.
It's also the resulting tapered chamber that causes so many of the crimp issues and rounds not fully going into battery that we see with this cartridge.
Once you realize and comprehend that subtle external difference in 9mm brass, you'll start to fully understand and really grow as a reloader of this cartridge. At least that's my hope.
.
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Well, I guess that's probably the answer. I measure the dimensions of all my brass with a micrometer during what I will refer to as "intake" inspection. In the case of 9mm, any case that can't pass the micrometer's jaws set to 0.3914 goes into the recycling bin.
Yes. I certainly have not needed one to date.
I shoot only range pick-up brass.
The pistol barrel is never called upon to doesn't identify such damage - nor should it be.
Such damage to the rim as you describe should be - and in my case always has been (so far at least) - caught during the case's
- Preliminary inspection,
- It's "intake" inspection (where it enters the "reloading stream" and which includes measurement of critical case dimensions with a micrometer),
- The visual inspection that takes place when the case is primed, and/or
- A second visual inspection when the primer is sealed.
Yes, sir.
I decided to take up reloading 9mm when I was given a bunch of brass. I didn't even own a 9mm pistol. As soon as I opened the Hornday manual and looked at the cartridge drawing, I very nearly closed the book back up and took the brass to the recycling center.
In the end I'm glad I didn't. But, I did have the devil's own time getting used to what you called the "subtle external difference" and the compromises the die makers have made in the tooling to deal with that slight taper.
Bingo, I just use the gauge where you use a micrometer.
Dudedog
Contributing Member
Just a side note, for me BE86 just didn't group well until I got up to the heavier side of the charge range, good there, not as good in the middle.
Higher than I wanted for 128-130ish PF loads. SDs and ES were good but results on paper were not as good as other powders at the 1030ish velocity range.
Higher than I wanted for 128-130ish PF loads. SDs and ES were good but results on paper were not as good as other powders at the 1030ish velocity range.
CoalTrain49
Member
Not quite as versatile as a micrometer but it never goes out of adjustment and I don't have to look up the SAMMI spec every time I use it.
Varminterror
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That is not correct. Pull the "Cartridge and Chamber Dimensions" PDF on their site - it clearly defines the throat and leade angles and lengths, with an overall length of the chamber from breechface to rifling (default, considering the rifling to start at the end of the leade).
Here's the problem with saying something like "chamber gauges are reamed to saami spec..." SAAMI spec is a range of dimensions, not a fixed dimension set, so a broad spectrum of dimension combinations can be "in spec." So personally, chamber gauges are worthless unless I know the reamer which was used to cut them was at minimum spec in every way, such the ammo would fit in any spec chamber, albeit fit loosely into a max spec chamber - and only then when I was producing ammunition under a Type 6.
If a guy reloads one load for multiple pistols - pistols in hand - then it is easy to figure out which one has (which ones have) the minimum dimensions for length and diameter, it's not rocket science. One of our first skills in mental development is to determine which shapes fit in which holes - loading ammunition is no different.
Pepa
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Have you considered taking your barrel out of the pistol and using it as a case gauge? I have case gauges for pistols and use the cylinders of the revolvers as case gauges. Just drop the first few rounds in and get your dies adjusted for the firearm. Check every so often to be sure. I'm in no hurry, so I also feel confident after I run every rifle round through the chamber before I store it away. One less thing to worry about when the time comes to use it.
CoalTrain49
Member
That was my feeling also. The dimensions (with tolerances) are there if you want use them.
I'm still trying to figure out why you think gauges are useless. I believe most gauges are min. tolerance. What would be the point in having a max. tolerance gauge? That would mean that ammo that passed a max. tolerance gauge wouldn't fit in a min. tolerance chamber. The point of a gauge is to know the ammo will fit in any chamber that meets SAMMI tolerances. Lets say the SAMMI drawing dimension is 0.400 and the tolerance is +/- 0.002. The chamber could be 0.398 or 0.402, or anything in between, and still be within spec. Thus the gauge needs to be the min. 0.398 to insure that the ammo will fit the tightest 0.398 SAMMI spec chamber.
If the ammo will fit a gauge and it chambers in your gun that's really all you need to know. The only trouble I've ever had with 45 ACP ammo for match barrels is cases over the min tolerance. If they gauge they chamber. The end.
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peterk1234
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Pulled the barrel out again to test two bullets that did not chamber properly from a couple of days ago. For the life of me and I could not find a measurable difference between those two and my other rounds. Interestingly, if I would slingshot the slide, even the "bad rounds" would eventually work, but the bullets definitely were being forced into the chamber. So back to the drawing board. This time I added a bit more crimp using the the fourth Lee FCD. I am talking just a tiny bit. The brass was not getting buried in the lead because I could feel the edge with my fingernail. Every round I made dropped in without any issues whatsoever.
Man, that is one tight chamber
The guys at the shop sent me a link explaining how to break in one of these guns. Basically, I have to fire enough rounds through it to heat it up. Let it cool a bit and do it again. Do not clean it, except to run a bore snake through the chamber, and keep it lubed. So, off to the range tomorrow to shoot 500 or so rounds. I can think of worse things to do.
Man, that is one tight chamber
The guys at the shop sent me a link explaining how to break in one of these guns. Basically, I have to fire enough rounds through it to heat it up. Let it cool a bit and do it again. Do not clean it, except to run a bore snake through the chamber, and keep it lubed. So, off to the range tomorrow to shoot 500 or so rounds. I can think of worse things to do.
mstreddy
Member
Peter, one other thing to check is the sizing of the cases. I have a lone wolf barrel for my Glock 17 and it is very tight. I have to size the 9MM cases way down. I use it as my "case gauge". If rounds fit in it, they will fit in every other 9MM I own.
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peterk1234
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When you say "sizing down", are you referring to trimming the cases? Which leads me to another rookie question.... When I plunk test, the good ones drop in and sound like the hit a solid wall. I would think that the edge of the brass is against the end of the chamber, but none of the diagrams I have looked at online indicate that is the case. Plus, for that to happen, all of my brass would have to be the same length......no feakin' way that is the case. So, what is that "solid wall" that the bullet is hitting? I just can't figure it out. I can't imagine it is the ogive, but maybe it is.
mstreddy
Member
Sizing down is just sizing the case. In my issue, if I don't size down to really tight on the press, the sized cases will not plunk in that barrel. Remember 9MM is tapered, so it's wider towards the base. 9MM headspaces on the mouth/rim. So, it does drop in and hit that "ledge" at the end of the chamber. Don't worry about case lengths in 9MM.
If your sized cases are plunking, then it's the bullet and thus OAL. It would then be the ogive. that is what affects the contact point of the bullet in the leade. Refer to RFwobbly's post #25 above. Those diagrams tell the story.
And, yes drawings don't show the case against the ledge or wall as you call it. But that is where they stop.
As to breaking-in period, that's for general function, it won't change a tight or short chamber. Some with some barrels are just tight or short. As Walkalong mentioned his EMP required some adjustments to his loads, I encountered it with the lone wolf barrel, CZs are known to have short leade chambers.
Apparently your STI is in this group.
So, I would suggest you size a few cases and plunk test them in the STI barrel. If they are good, then make up a few rounds to test the crimp after seating the bullet. At this point you will find if you need to adjust your OAL to get the plunk.
As to factory ammo, if your STI doesn't like it, then shoot it in another gun. Work to get your reloads to match your "match" gun.
If your sized cases are plunking, then it's the bullet and thus OAL. It would then be the ogive. that is what affects the contact point of the bullet in the leade. Refer to RFwobbly's post #25 above. Those diagrams tell the story.
And, yes drawings don't show the case against the ledge or wall as you call it. But that is where they stop.
As to breaking-in period, that's for general function, it won't change a tight or short chamber. Some with some barrels are just tight or short. As Walkalong mentioned his EMP required some adjustments to his loads, I encountered it with the lone wolf barrel, CZs are known to have short leade chambers.
Apparently your STI is in this group.
So, I would suggest you size a few cases and plunk test them in the STI barrel. If they are good, then make up a few rounds to test the crimp after seating the bullet. At this point you will find if you need to adjust your OAL to get the plunk.
As to factory ammo, if your STI doesn't like it, then shoot it in another gun. Work to get your reloads to match your "match" gun.
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My issue was never OAL, or crimp (I barely touch the case mouth), but a fat case at the base just above the rim (Over .391). Sounds like his problems may include that, but not just that. I would love to see a Cerrosafe cast of that chamber.My chamber was also undersized before they reamed it, but only to SAMMI minimum.
A great test would be to load up some brand new brass.
A great test would be to load up some brand new brass.
mstreddy
Member
Walkalong,
I agree, I think he may have a tight chamber with a short leade. I didn't write the above correctly. The issues are different, but I wanted him to understand that there are issues.
I agree, I think he may have a tight chamber with a short leade. I didn't write the above correctly. The issues are different, but I wanted him to understand that there are issues.
Dudedog
Contributing Member
Not BE86 but maybe helpful to give you an idea of the effect of OAL on velocity
I just did a quick OAL test of the new RMR MPR 9mm JHPs at different OALs.
(I had been out in the heat for about 5 hours and was tired after a match so I didn't try anny accuracy testing, just chrono)
These were all a mild load of WSF, I would imagine heavier loads would show a more pronounced difference.
Mized Range Brass, S+B SP, 4.0gr WSF
5" 9mm 1911
Temp 107 ish
OAL 1.08
981 121.64 265.04
966 119.78 257.00
977 121.15 262.89
955 118.42 251.18
948 117.55 247.51
Avg 965.40
Lo 948.00
Hi 981.00
ES 33.00
SD 14.05
OAL 1.065
975 120.90 261.81
989 122.64 269.38
960 119.04 253.82
988 122.51 268.84
976 121.02 262.35
Avg 977.60
Lo 960.00
Hi 989.00
ES 29.00
SD 11.80
OAL 1.055
992 123.01 271.02
983 121.89 266.12
987 122.39 268.29
977 121.15 262.89
1010 125.24 280.94
Avg 989.80
Lo 977.00
Hi 1010.00
ES 33.00
SD 12.56
OAL 1.04
989 122.64 269.38
1003 124.37 277.06
1012 125.49 282.06
995 123.38 272.66
1007 124.87 279.28
Avg 1001.20
Lo 989.00
Hi 1012.00
ES 23.00
SD 9.23
So with this bullet and powder/powder charge going from 1.08 to 1.04 showed an increase of about 36fps average.
I just did a quick OAL test of the new RMR MPR 9mm JHPs at different OALs.
(I had been out in the heat for about 5 hours and was tired after a match so I didn't try anny accuracy testing, just chrono)
These were all a mild load of WSF, I would imagine heavier loads would show a more pronounced difference.
Mized Range Brass, S+B SP, 4.0gr WSF
5" 9mm 1911
Temp 107 ish
OAL 1.08
981 121.64 265.04
966 119.78 257.00
977 121.15 262.89
955 118.42 251.18
948 117.55 247.51
Avg 965.40
Lo 948.00
Hi 981.00
ES 33.00
SD 14.05
OAL 1.065
975 120.90 261.81
989 122.64 269.38
960 119.04 253.82
988 122.51 268.84
976 121.02 262.35
Avg 977.60
Lo 960.00
Hi 989.00
ES 29.00
SD 11.80
OAL 1.055
992 123.01 271.02
983 121.89 266.12
987 122.39 268.29
977 121.15 262.89
1010 125.24 280.94
Avg 989.80
Lo 977.00
Hi 1010.00
ES 33.00
SD 12.56
OAL 1.04
989 122.64 269.38
1003 124.37 277.06
1012 125.49 282.06
995 123.38 272.66
1007 124.87 279.28
Avg 1001.20
Lo 989.00
Hi 1012.00
ES 23.00
SD 9.23
So with this bullet and powder/powder charge going from 1.08 to 1.04 showed an increase of about 36fps average.
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