Mg 124 jhp col?

[john16443]

I remember reading somewhere that the bullet body dimensions for the Montana Gold 115/124 JHP's are the same as the Hornady 115/124 XTP's. Can someone confirm this?

Also, if you're shooting the 124g MG JHP's, what COL are you using? I'm asking because if the statement above is true, then the COL I should be using for the MG 124 JHP's should be about 1.06 or more according to the Hornady manual, but I keep finding information that says folks load the MG's to 1.12"

I've loaded 4.0g Titegroup with the 124 MG JHP's to 1.12" and they don't seem near as accurate as many folks seem to find them. Thinking about reducing COL to 1.08" with the same 4.0g TG.

Thoughts??

 

[frankt]

Sorry to be late to the party.

I have been loading the MG 124 JHP to 1.09 ever since I started shooting them. They have functioned great in two different Glocks and a XDM.

I use W231 as I load three different calibers for IDPA and I can make this powder work for all three.

TG has always been too snappy for me.

 

[john16443]

Frank - I've continued to experiment with COL and powders. I'm trying to settle on W231 for the 9mm and 45ACP as well. Function isn't a problem in my 9mm, but they don't seem to group that well, even compared to RN.

1.10" and 1.12" have worked, but haven't shown that they are any more accurate off-hand than regular RN. For your COL of 1.09, can I ask what charge of 231 you prefer? My range so far has been between 4.1 and 4.6 grains of W231, with 4.4 grains @1.12" COL showing the most promise.

Thanks;

 

[1SOW]

john,

I remember reading somewhere that the bullet body dimensions for the Montana Gold 115/124 JHP's are the same as the Hornady 115/124 XTP's. Can someone confirm this?

I assume your talking about your "Ruger"? The reason I ask is that it's "YOUR" pistol chamber that limits the max usable OAL of different bullet nose profiles. It will not be the same as another pistol.

In my CZ, the MG 124 JHP with a conical nose has to be loaded at 1.10 or shorter. Your pistol won't likely be the same. Reloading data will give an oal-powder combination that is safe at THAT oal OR LONGER, but NOT shorter. If the data shows an oal of say 1.08", I can use it; because it's safe to load a "longer" oal. If data shows the OAL at 1.11", I CAN'T use it, because it won't chamber in my pistol at that length and it's NOT safe to load shorter than the load data gives.


If Hornady gives a 1.06" oal for that bullet, then you can load longer safely as long as the bullet nose doesn't contact the rifling/cone and cause pressure spike problems.

What someone else uses with a different pistol and chamber doesn't give you a good oal unless you're just lucky.

The conical nose HPs are usually the ones that have to be loaded the shortest for a given bullet weight to prevent contact with the rifling/forcing cone when chambered.. HPs with a regular ogive may be able to load a little longer. FPs also usually need to be loaded horter. CZs and XDs usually have the shortest headspace for these type bullets. Glocks usually allow much long oals for these bullets.
Yours will be different.
A dummy cartridge "Drop-IN" test can tell you the longest oal "your" pistol with that "specific brand and nose-type can handle . A search will show good pics and instructions for the test from "rfwobbly" and others.
Hope this makes sense..

 

[ConcernedCitizen]

1.100" works for my XD9, which didn't like them any longer than 1.112". It can chamber FMJ at 1.150" without any trouble, though.

My Glock barrels will chamber the JHP at 1.135" without any trouble, but I haven't tried anything longer than that yet.

I settled on 1.100" because it will feed in both the Glocks and the XD, and it gives an extra 0.010" cushion before I start to hit the rifling on the XD. It also seems to be a very common length according to my research.

As many before me have recommended, use your barrel to determine your max OAL, and use that as a starting point.

Good luck!

 

[john16443]

1SOW - Yes, I am talking about my Ruger, which has a very "generous" chamber that will allow rounds of various lengths and bullet shapes to pass the barrel plunk test with ease. As a matter of fact, the plunk test will pass with bullets of many different profiles loaded to lengths well in excess of the SAMMI dimension of 1.169". They won't fit in the magazine of course, but the plunk into the barrel nicely.

So I know the Ruger will accept them all the way out to max, and I've decided that my max loading length for any round would be 1.155".

Knowing this, my question now becomes what COL would 'most likely' result in the highest probability of the tightest groups on paper IN MY GUN? Loading them short to 1.06 or loading them long to 1.15, recognizing that MY gun will function fine at either end of the spectrum and anywhere in between.

 

[1SOW]

john, I can't answer for your pistol, but I do know many competitors who shoot light load 'target' JHPs at 1.09"-1.125" because of the JHP accuracy in their pistols. I use the Zero 125gr JHP at 1.10" and it's very accurate in my CZ. I have used 231 with similar results.

Truthfully, I've had some 124gr hbrn Berry's bullets that shot light loads with similar accuracy. Both of these bullets have increased rifling contact due to bullet design. More of the lead is in the straight sidewall rather than the nose. I shot the Berry's bullet at 1.132" because it worked well in my pistol through trial and error. With more powder a longer oal may have worked just as well. My pistol "feeds" RN cartridges at 1.132" with 100% reliablity.







.

 

[REL1203]

I use MG JHP 124 bullets for my comp gun, and run them at 1.1" exactly, and they feed great in my XDM 5.25, G19, G26, and 92FS.