9Major Crimp?

[HazB_Shootin]

Hello All,

I just started loading 9Major again for use in my SV open gun and ran into an issue today at the range while testing my first loads. Some of the the bullets are actually separating from the case during feeding. They seem fine when handling/loading the mag, but came loose after shooting a few times. I'm assuming the vibration from firing worked them loose in the mag.

Of course the issue is not enough case tension on the bullet, but I was wondering which way to go to resolve it. One way would be to keep the OAL I would like to use (1.170) and add a taper crimp (none added on the ones I shot today) the other would be to reduce the OAL to something like 1.160 to force the bullet down in the case a bit more for more tension.

From what I've seen 1.170 seems to be a common OAL, so I'm guessing that adding a taper crimp is a better way to go - am I missing anything here? Is taper crimping a known thing to do for 9Major?

My test load from today:

RMR 124gr .355

9.1 gr HS6

Mixed Brass

1.170 OAL

CCI SRP

All cases were put through a Lee U die and not excessively opened at the case mouth during the powder charge - the bullet will just barely sit on top of the case prior to seating.

All LEE dies.

BTW - the ones that shot were great, very good accuracy and mild recoil - PF a little low at ~167 but that may be somewhat due to the lack of case tension on the bullet (less pressure).

[wes777]

crimp to -.003 under bullet + (2 x case wall) thickness.

[Hi-Power Jack]

. Some of the the bullets are separating from the case during feeding.

the issue is not enough case tension on the bullet, . One way would be to keep the OAL I would like to use (1.170) and add a taper crimp (none added on the ones I shot today) the other would be to reduce the OAL to something like 1.160 to force the bullet down in the case .

From what I've seen 1.170 seems to be a common OAL, so I'm guessing that adding a taper crimp is a better way to go - am I missing anything here? Is taper crimping a known thing to do for 9Major?

RMR 124gr .355

9.1 gr HS6

1.170 OAL

All cases were put through a Lee U die

You don't have much bullet in the case at 1.17" - I'd certainly try 1.16" and see if that works.

You do want a taper crimp, but I'm sure you're already getting one with that reloading gear.

[Jaxshooter]

_{I have been shooting 9 major since they made it legal. I use a Lee Factory crimp die on all of my 9 mm major loads and never have a problem. My OAL is 1.165 using a MG 124 JHP, MG 124 CMJ or the MG 121 IFP. You should notn the brass.be relying on the crimp to hold the rounds together that is done with neck tension}

[Steve RA]

Resize the brass to a smaller diameter so you get the "wasp waist" effect, you want the case tension to hold the bullet securely, not crimp. Just crimp enough to remove the bell from the case mouth. Cases vary in wall thickness, it makes it easier if you sort cases by brand and learn what you need to do to each brand.

[EkuJustice]

if you are using 9.1 grains of HS6 with a 124 grain bullet and only getting 167 PF something is seriously wrong.

I load mine with 8.2 grain and a 124 and am in the 175-176 range at the same 1.17 OAL. I basically do mine with VERY little if any belling and stabilize the bullet on the down stroke and mine does not move at all when pushing it on the bench

[HazB_Shootin]

Thanks for the replies, much appreciated.

I just got home and read these when it dawned on me that the 124gr bullets I'm using are flat points. So I mic'ed a RN then the FP I was using and the FP is 0.029 shorter than the RN. No wonder, seated to the same OAL the RN will seat deeper in the case. Plus I found a few rounds leftover from today actually at 1.175. I'm going to try 1.165 and keep a closer eye on the OAL. I may add a very slight crimp but I understand that's not what keeps the bullet from setback or in this case falling out - its case tension.Thanks again for the quick responses.

[gng4life]

Thanks for the replies, much appreciated.

I just got home and read these when it dawned on me that the 124gr bullets I'm using are flat points. So I mic'ed a RN then the FP I was using and the FP is 0.029 shorter than the RN. No wonder, seated to the same OAL the RN will seat deeper in the case. Plus I found a few rounds leftover from today actually at 1.175. I'm going to try 1.165 and keep a closer eye on the OAL. I may add a very slight crimp but I understand that's not what keeps the bullet from setback or in this case falling out - its case tension.Thanks again for the quick responses.

Are you seriously using 9.1 with a 124?? What barrel and holes? Please make sure of this as this seems like something wrong, just as Eku said. I have a slow (very slow) TruBore with two popple holes and it only took me 8.5-8.6 to get 170-171 PF. Most use about 8.1-8.2 and in my KKM barrel, 5", no holes, I'm using 8.1 also. Even in my shorty with two holes, it only took 8.6. Most people use 9.1-9.2 for a 115 and that's with popple holes.

Please make sure to check your loads again, that sounds dangerous.

Yeah, also FP, JHP, and FMJ will all have different OAL due to the ogive/tip configuration.

[Jman]

if you are using 9.1 grains of HS6 with a 124 grain bullet and only getting 167 PF something is seriously wrong.

I load mine with 8.2 grain and a 124 and am in the 175-176 range at the same 1.17 OAL. I basically do mine with VERY little if any belling and stabilize the bullet on the down stroke and mine does not move at all when pushing it on the bench

...this

[HazB_Shootin]

Thanks for the warning, now that these should be seated better I'll drop the charge to 8.2 and see what those do My open gun has a commander length slide so the barrel is 4.8" to back of the hood and the comp is a EGW 7 port, no popple holes. I would like the PF to get around 170 but if 9.1 sounds way high then I'll heed the warning

[Hi-Power Jack]

I'll drop the charge to 8.2

HazB, drop 10 charges and weigh them together - see if they weigh 82 grains.

[RockinRiley]

The books I have usually have a load for flatpoint, that way you can see the oal you need. Please refer to your load manuals! Use more than one and if they do not agree, then work out a load carefully. At 1.170 I would suggest you try a plop test on your barrel, as a flat point may be hitting the rifling at that length!

[EkuJustice]

Mine is a full size but I do have popple holes in the barrel. I get like 175 pf at 8.2 and 8.5 gets me 180pf with a 124 Montana gold Cmj at 1.17. A shorty with no holes should be in that range. How are you checking your pf on a chrono ie how far back are you as you need to be back a little more with an open gun. Your powder charge is what alot are using with a 115 grain bullet

[HazB_Shootin]

I measure PF with a chrono @ 10feet out. Does that sound possibly to far? Come to think of it when I chrono at major matches it usually comes out ~3 PF points higher than my readings. Hmmm...

[Hi-Power Jack]

I measure PF with a chrono @ 10feet out. Does that sound possibly to far? Come to think of it when I chrono at major matches it usually comes out ~3 PF points higher than my readings. Hmmm...

10 feet is perfect.

[gng4life]

10-12 feet is perfect, any closer and you start to get false readings...