Bullet weight discussion

[sdlsaginaw]

I pretty much settled on the 115gr being the round of choice in the R9, but it appears alot of talk is happening around the 147gr again.  I imagine the 147gr is being revisited since it's becoming the only weight you can still find.  I had avoided the 147gr due to earlier reports of keyholing.  

I know consensus says that "heavier is better", but is this really true in such a small pistol as the R9?  Is the R9 able to get the 147gr up to speed and stable?  Is the rifling sufficent for this weight?  Were the early reports just sour grapes?

I know I don't want to spend a buck a round for a high-end controlled expansion JHP so it can hit its mark sideways..  

Anyway, just wondering if anyone has found some good science out there regarding "more weight" vs "more velocity" in a short barreled pistol, and how well this applies to the R9.  Also, has anyone heard feedback from the R brothers on this topic?

[update] I just found this discussion on the forum http://www.rohrbaughforum.com/YaBB.cgi?board=R9S;action=display;num=1155009072

[Richard S]

sdlsaginaw:

That link certainly takes me back a couple or three years! Since then I rejoined the 147-grain school of thought based on my own experimentation at the range. However, anecdotal recitations unsupported by photographic evidence are of little value except to the one making them.  Perhaps I should do another round of testing, this time taking my camera along, and see if I reach the same conclusion again.

Thanks for resurrecting an interesting topic.

[ACP]

I cannot find 9MM ammo in 115 or 124 grain so I went with what I could find: 147 grain (Golden Sabre & Hornady TAP).

Expensive? Yes; but it is also the best shooting experience I have had with the four (4) R9s I have owned.

I am unfamiliar with the study that may have dealt with esoteric aspects of 147 grain usage. I do, however, know that these bullets go boom and make me happy.

[kjtrains]

That's what counts!      

[Bill_in_TX]

An interesting note.

When I queried the gal at Rohrbaugh (Maria?, maybe) about what the problem was with +p ammo, she didn't really give me a straight answer, but ended the conversation with "and no 147 grain loads either".

I think that the general trend toward 147 grain loads is an over reaction to the failings of the 115 grain loads.  The majority of the 115 gr loads don't meet FBI minimum penetration standards, so I think that many LE departments just swung comletely the other way and a lot of civilians simply followed their lead (just personal opinion -- I've looked at a bunch of the penetration results, but I'm just guessing on the reaction only because most of the 124 grs do meet the same standards).

In my own R9s I'd be pretty hesistant to use the 147 grs, not due to any weight-associated recoil or gun battering but simply bullet length.  I tried several different 124 grain loads when I first tested my pistol.  Even some of the longer 124 grain loads (i.e. deeper HP designs, like the Federal Bonded) showed very noticeable keyholing at 7 and 15 yds.  Since the 147 gr bullets are even longer, I would expect the keyholing to only be worse.  

Keyholing might be great in a really high velocity round like 5.56 where it would likely contribute to fragmentation, I don't believe that it's desirable at the substantially lower velocities of a handgun round.

I've settled on the 124 gr Speer GDs, myself, and buy a box or two whenever I find them.  They are one of the loads that meet FBI test standards (albeit at higher, service pistol velocities) and don't show any keyholing in my copy of the R9.

As a side note, I was attemping to research the twist rate a bit and came up short.  Standard 9MM rifling is 1:10.  Does anyone know what the R9 barrel twist is?

[tracker]

Karl knows the answer to that one. One source said in comparing a
Kahr PM-9 to the R-9 that the Kahr had a 1-10" twist while the R9
"appeared" to have about half that rate. If true, this would reduce
the kick but might tend to keyhole with heavier weight bullets.

This is just subjective speculation.

[ACP]

Bill's comments and Tracker's response are relevant and interesting. I will gladly try the 124 grain 9MM. Just tell me where I can buy them.

[sdlsaginaw]

Interesting quotes from the rebuttal to the Gun Tests article:

"Our rifling is a 1:16 right hand twist - a standard for 9mm in the industry"

and

"Due to breech size, the feed ramp is at a higher angle than other larger pistols and subsequently cannot feed the longer 147-grain truncated cone."

[Bill_in_TX]

Interesting quotes from the rebuttal to the Gun Tests article:

"Our rifling is a 1:16 right hand twist - a standard for 9mm in the industry"

and

"Due to breech size, the feed ramp is at a higher angle than other larger pistols and subsequently cannot feed the longer 147-grain truncated cone."

Thank you.  The first part answers my question about twist rate -- although AFAIK it's no standard in the industry for 9MM.  I never did go beyond my Sig manuals, but every Sig model that is available in 9MM has a 1:10 twist for that 9MM.

It is, however, a psuedo standard for the higher velocity cartridges that happen to use 9MM bullets, like the 357Sig and 38 Super (sort of a 9MM, anyway).  However, these get their stabilizing RPM by pushing the bullet through a shallower twist at a faster speed.

That twist would account for the problems with stabilizing any of the longer bullets (and it is actually length rather than weight that we worry about for twist) -- especially at the slower speeds we get from the R9.

The second comment is interesting given that a number of people here report using 147 grain, presumably HPs, that should actually be longer than any solid, truncated cone or otherwise, because they have to make up for the hole.

[Bill_in_TX]

Bill's comments and Tracker's response are relevant and interesting. I will gladly try the 124 grain 9MM. Just tell me where I can buy them.

I can't give you a specific answer to that.  I've found mine by just checking every gun shop that I go into.  Frequently enough, here in TX, I've still found a box or two of the Speer to keep up with the limited times I shoot the R9.

That said, the prices have been double (or more) what I paid for Speer 357Sig when I loaded up on those before the craze started.

[Fireball7709]

FWIW, and being that I could only find Hornady TAP ammo in 147 gr, that's what I've used so far.  I haven't shot paper at past about 12 yards, but have not seen any evidence of keyholing and they have functioned and fired fine.  I tend to ride with the heavy bullet camp anyway.

[Richard S]

It gets even more interesting when you factor in the OAL data of various brands and loads which Chris posted in the FAQ site at this link:

http://www.acbsystems.com/boards/rohrbaugh/basefile/tumbling.htm

[kjtrains]

I'm keeping my backorder in for the 147 gr. Golden Sabres.  

[ACP]

I happened onto the 147 grain because that is all I have been able to find, for which I have commented on a different string.

There is a small local gunshow this weekend and I am bracing for 9MM prices, (if they have any available), in the recommended Silver Tip or Gold Dot. If so, I will buy 115, 124 & 147 grain ammo.

I had never used the 147 grain bullet in an R9 and my first empirical concern was the bullet length. That concern went away as soon as I pulled the trigger.

Had it not been for Richard's posts (as to the virtue of 147 grain Golden Sabre) I may have passed up this opportunity. As it is, I have 200 rounds (only) of 147 grain and am grateful to have it, given what is going on.

[Richard S]

One reference which I have found informative on this general subject is the report entitled “Handgun Wounding Factors and Effectiveness” by Special Agent Urey W. Patrick of the FBI Academy Firearms Training Unit. Although this report was published twenty years ago in 1989, it remains, as stated in its Forward, "an important contribution to what should be an ongoing discussion" involving the use of handguns for self defense. Pages 11 and 12 of the report discussing criteria for selecting ammunition are particularly interesting.

Although the report was created for law enforcement use, it is now available in the public domain at the following web site:

http://www.firearmstactical.com/hwfe.htm .