Could Ammo Lot Variations Be Causing Some FTF?

[MountainMan]

On the Seecamp forum Larry Seecamp is very frustrated because quality control seems to have gone out the window at many ammo factories.

The Seecamp has very tight tolerances (like the R9) and because of this is ammo senitive (like the R9).  For the first time Seecamp was getting complaints of FTF.  People would send the pistols back - no problems.  Then the owner would get the Seecamp back and shot the same ammo as was recommended by Seecamp and FTF.

The problem - more variations than in the past in Ammo Lots as far as specifications.  The lots the customers had that were having FTF the rounds were slightly longer - the seating of the bullets were out more.

In a small tight tolerance gun this makes a huge difference.

Could be a reason for some problems with the R9.  We have had some who go through  a box of ammo - no problems.  Then go out again and FTF problems - same ammo brand - but is it a different lot?

May sound crazy but if you are having a FTF keep some rounds  - if you have a caliber measure them.  Go and buy from a different lot - measure them.  If they are a little shorter give them a try.  If they work save enough of that lot for carry.

We have had forum member who say that they will not trust the R9 for carry until they can go say 200 rounds without a FTF.  Then again that is not taking in the ammo lot variation problems.

Who ever thougt that you would need a caliber when buying ammo.

Here is a link to the Seecamp thread on this subject.  You will see a very frustrated Larry Seecamp to a point he is thinking that maybe they should produce their own ammo.

http://seecamp.com/cgi-bin/yabb/YaBB.pl/YaBB.pl?board=ammo;action=display;num=1148078312;start=0#0

[sslater]

I checked out the Seecamp website for Larry Seecamp's comments.  Pretty frustrating.  
From what little I know about handloading, setting bullet seating depth (and overall length) is one of the normal tasks you go thru in making ammo.  Only case length and bullet length are involved, so it's reasonable to expect commercial loads would held pretty consistent.  
Hmmm....I guess that's expecting too much.  Like legroom on your airline seat.  

Anyway, maybe I'll pick up a 9 mm parabellum overall length gage from Midway or Brownell's.  That would be a little less intrusive than walking into a gun shop and whipping out your digital calipers.  Actually, being cheap, I'll probably trim a length of pipe to the appropriate length and save myself $12.

There was a suggestion recently (on this forum??) to save 6 or 7 rounds from each box of ammo that fires flawlessly.  Those saved rounds go into your carry magazines.  You could also use those rounds to set up your home made cartridge length gage.  And to complicate things, different brands will have slightly "optimum" overall length due to differences in bullet profile, won't they?

No wonder mini gun manufacturers like Seecamp and Rohrbaugh get prematurely old!!

[Michigunner]

Thanks for that excellent information.  

I have owned a high-grade Starrett micrometer for many years.  Finally, it may be put to use.

If I can get through most of a box of Silvertips, there is no doubt the last 14 will be put aside for carry.

[RJ HEDLEY]

This could be just another factor to enter into the picture.

[harrydog]

Yes, I think it may be another variable to add to complexity of getting the gun to work properly, but not the only factor.

[MountainMan]

Another ammo area to consider is if the round is too short - this also can cause FTF.

Seecamp stopped recommending the new .32 silvertips because after a few shots some of the rounds in the magazine would at times have the bullet recede into the case some causing a FTF because of a bad crimp.

So if you are getting a FTF on the third round or so take it out before it is fired and measure it.  Is it slightly smaller than a round still in the box.  If so that lot of ammo may have bad crimps.

Where on a small tight tolerance gun this also could cause a FTF - it has been proven to do so on Seecamps.

Just another area to consider.

[capt.koolaid]

Thats the problem with, and one of the reasons Ive never bought a ammo specific gun and never would! The company may drop the design, the manufacturer may go out of buissiness, ( Oh I miss Triton!). Funny thing about that is I never bought a Seecamp for that very reason! My wife bought me a Seecamp LSW 380 and it digests EVERYTHING ive put thru it! I Bought the R-9 because it wasnt ammo specific and well.....to be continued

[Aglifter]

My R9S has eaten absolutely everything -- never a hiccup -- admittedly, it doesn't get fed some of the really nasty stuff I put through my 1911/XD, but about 150 rounds w/o a problem.

[R9SCarry]

Let me repeat the pic below - just a few examples of ammo and OAL variations.  The Blazer on right BTW is to all intents a GD in aluminum case - same bullet and OAL is all but identical.

I do feel the longer OAL is useful for two reasons.  First off, as the round is strpped from the mag there is a better chance of starting into the chamber than with shorter - where just perhaps that frustrating ''tipped up'' round jam can occur - in other words the round's bullet does not get an early enough start being chambered and jams on top of chamber mouth - something I also think can occur with a very dirty gun..

Second thing not, in same category, is - with the 1/4" freebore, I fancy the longer round reduces bullet jump distance and so helps better aligned engraving and reduced tumbling potential.

[capt.koolaid]

R9S carry: Your post is very impressive. You have raised a very valid and interesting hypothosis!

Now, Bare with me, Im not a gunsmith or the sharpest tool in the shed but im starting to wonder about something and maybe you can shed some light on this subject. Anyone else feel free to do so as well. Here gos: Ive heard talk of the Rohrbaugh "free bore" in the barrel. I see by the posts its 1/4" long. I dont have calipres, micrometers, etc. but looking down the barrel of mine it appears the barrels rifleing is all the way thru the length of the barrel, (save the front portion were the round is seated in its chamber of course) One of our resident "gun nuts" says its supposed to have a "free bore" area to assist in bleeding off pressure from the round so the locking mechanism works reliably in the R-9 due to its small size. He also said this is what tends to lend the Rohrbaugh to "keyholeing" its rounds and in essence, reduces the muzzle velocity and gas pressures in the 9x19 round down to an approx .380 +p a.c.p. rounds velocity in the Rohrbaugh and as such thats why he never bothered to get one. I wonder if thats why Seecamp never introduced a 9mm? At anyrate, Is it possible Ive a faulty barrel? Or is the "freebore" space so small its undetectable without calipres? or....Am I lost here and talking of something totaly differant?

[R9SCarry]

Capt -

Let me use this pic of one of my barrels.  The main and obvious change in dia is where the case headspaces - but you'll see beyond that the freebore area, before the rifling starts.  Remember the full bullet diameter is within the case until fired and so no bullet to rifling contact, until after the ''jump''.

I cannot other than assume your barrel will be identical!

The reduction of pressure peak is important but small - it is a limiting factor and not a pressure loss.  If you look thru my test data on various ammo thru R9 you'll see that the 9mm performance as std pressure is what would be expected - not IMO anything like ''.380 +P'' - well not IMHO.  Here is my ammo data page.

If you consider this ammo is coming out of a short barrel - velocities around 1,000 fps are both presentable and to me, proper 9mm - in fact I have not met or tested any .380 +P ever anyways - and they would use a 95 or 97 grain bullet IIRC - as against our perhaps 115 or 124 typically.

That pressure peak protection BTW is really only an extension od the dimilar practice in rifles - should a bullet not have a ''jump'' space then pressure builds inside the case to excess as bullet engraves too early - it must have that acceleration time and so immense inertia - to commence that friction-heavy engraving journey.  Bros R just made that jump a shade bigger than usual - to ensure no serious excess during transition.  remember too the 9mm is by nature a very high pressure round anyways.

Does any of this help?  Hope it might in part at least.

[capt.koolaid]

R9S: YES! it helps me understand. I appreciate your time and effort on this because of the "free bore" issue. I chose the Rohrbaugh system because even if what he said was true about +P .380s, I knew the 9mm X 19 round would be offered in greater wieghts and I felt if the whole "tumbling/keyhole" thing was realy happening, certainly a 147 grain bullet with a longer area of engagement and taller projectile to tumble end over end would be one wicked wound channel if God forbid it were ever needed. That being said, looking at your posted picture i doubt its 1/4". was that a type-o or am i misunderstood? At any rate Id greatly appreciate your feed back on the keyhole/tumble phenomina. Do you find this to happen often and with specific grain weights or brands? Once again thank-you for your follow-up.

[Michigunner]

Chris,

You're the best picture taker I've ever seen in my whole life.

Nice job.

[R9SCarry]

Bill - you are too kind but I cannot accept that fully, as I know of so many way beyond me in quality etc - Oleg Volk on THR Owner) is one example.  I thank you anyways (I have been ''at it'' a long time!).  His site BTW is worth a look, not only for his pic galleries - http://www.a-human-right.com/ - take a peek when you have a few minutes.



Capt' - the quoted freebore is listed as .250" in their literature, and tho I haven't checked, think mention may be made on their own web site.  I know the pic looks nothing like 1/4" - but to help you see how much perspective compression we have - study the chamber itself - does that look as long as a 3/4" 9mm case??  Not here is doesn't I reckon!  The rifled section too - does not look like its actual near 2".  Deceptive

I have not measured the freebore for myself but can accept the dimension given as accurate.

The tumbling issue - well I have a page on my FAQ site discussing the tumbling and there is a pic - hmm, let's see ........... THIS PAGE

On that page is this pic, below - which shows how engraving can go off axis - look at the bullet grooves.  Now this was a poor expansion due to some tumble thus asymmetrical - but forget offhand the ammo used.  Suffice to say this was one bullet that started to engrave just a smidgeon off-axis - the error occurring during the jump.  Now I find this is not a consistent problem at all - even in an ammo batch that might seem prone to it, it will not occur every time.  Even this bullet IMO could inflict some serious damage!!

I suspect (theory only) that the lighter bullets might be more prone - as the ogive may be relatively shorter and the driving region shorter - this effectively making the jump distance even more exaggerated.  Add to that perhaps too - a shoter than usual OAL and again - bigger effective jump.

[jarcher]

WARNING - RANT MODE ON

Good grief, what next?  Are we going to start discussing whether changes in the case size due the ambient tempature being very high (July in Arizona) or very low (February in Maine) impact reliability?

There are specifications which define the various characteristics of ammo.  My attitude, which I firmly believe is very reasonable, is that if the ammo is in spec, it should work in a pistol and if it does not there is an issue with the pistol.  If the ammo is out of spec, well then that's another story.  

I didn't read that entire thread, but the only question I would have is whether or not the ammo is in spec.  If Federal changes it's hydra shok ammo but the change leaves the round still in spec, I don't see an issue with the ammo.  These changes are to be expected; it's no suprise when an ammo maker changes their ammo.  If they can find a way to make it work better or be produced cheaper, they are going to make that change and they should make that change.

If a pistol is ammo specific or ammo sensitive, then let's just say so.  Let the buyer decide if they want to take that risk.

PS - I intend no disrespect to Larry Seecamp or any other pistol maker, but I do feel my position is reasonable.