Author Topic: Cartridge O.A.L.  (Read 4652 times)

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Cartridge O.A.L.
« on: April 25, 2013, 08:27:24 AM »
I have been amazed at the accuracy of my 75BD .  So I tried a technique that is often used on rifle ammo to get maximum accuracy.  I "PUSHED" a 9mm case with a bullet setting slightly in it into the chamber of my pistol barrel.  A 124 FMJ from Delta Precision gave me a reading of 1.220".  So I made some 1.205" rounds to try out.  They worked great if you single loaded them into the pistol.  The magazine will not accept anything longer than 1.166"  So I am back to an O.A.L of 1.160" for more rapid fire.

Steve H.

  • Guest
Re: Cartridge O.A.L.
« Reply #1 on: June 30, 2013, 11:55:38 PM »
Hi R.Fierro,
I just tried (couldn't sleep) this process. Only I allowed my slide release to do my pushing (old fingers what can I say). 75 (pre B) showed exactly 1.169" oal chamber. Magazine works well with same.

For the past month. I've been working up my load with Hodgdon Recipe: 125 LCN Bullet, IMR - SR4756 Powder @ 1.125" oal. Starting to show a little better accuracy at 4.6gr. (near high end) 4.8gr. is max. for this load.

I was going to try 4.5, 4.6 & 4.7 grain for this weeks testing for accuracy.

Hodgdon does have recipe for 124gr LRN & 147gr. Lead CFP. Using Winchester WSF Powder @ 1.169" oal.

Do you think this will give me better accuracy with 75 (pre B) ???

Thank you / Steve H.

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: Cartridge O.A.L.
« Reply #2 on: July 01, 2013, 07:51:05 AM »

Do you think this will give me better accuracy with 75 (pre B) ???

Thank you / Steve H.
The load may be more or less accurate.  It depends if you are shooting as accurately as possible with the gun to compare results.  If you are shooting, say a two inch group at ten yards and the gun/load is capable of one inch.  Then you will only see a difference if the load is worse than two inches.   
 

Steve H.

  • Guest
Re: Cartridge O.A.L.
« Reply #3 on: July 01, 2013, 09:03:09 AM »
I'm interested in knowing more on "OAL" in pistol chamber. As you mentioned above.

Will a recipe perform better if full length of chamber is used or if possible to max. (of course going a little less so all will function properly). In my case chamber 1.169",  I've seen charts of 9mm cartridges. They show max. size of 9mm cartridge is 1.169"
Should one seek recipe to match their gun chamber ???
Of course each gun is different. But, just talking in general terms.  ????

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: Cartridge O.A.L.
« Reply #4 on: July 01, 2013, 10:28:20 AM »
Factory ammo will not exceed the 1.169" spec.  The Remington ammo on my shelf measures 1.120" while the Federal reads 1.150".  Comparing these two ammos in the same gun will give you an indication of how much variation in group size.  Theoretically the Federal would shoot better in a gun with 1.169" chamber.   
How much better would 1.165" shoot than 1.150"?  You would have to test to see.   The advantage might be the peace of mind that you are making the best ammo possible for that gun.   But unless you do the test you will not know if it is true.  My guess is that there is only a slight difference in a handgun.  Possibly too small to notice.  A rifle is more likely to show the difference from O.A.L. changes.
 
 

Offline noylj

  • Newbie
  • *
  • Posts: 26
Re: Cartridge O.A.L.
« Reply #5 on: July 08, 2013, 12:13:26 AM »
COL:
FMJ-RN is NOT a target bullet. Try a JHP. For real "target" accuracy, try a L-SWC (115-125gn) such that the shoulder just touches the lede/rifling. This will be within your magazine's COL range and be a lot more accurate than almost ANY RN.

Offline Rodolfo Fierro

  • Global Moderator
  • Hero Member
  • *****
  • Posts: 640
    • TRAIN 2 SHOOT
Re: Cartridge O.A.L.
« Reply #6 on: July 09, 2013, 01:11:37 PM »
I'll have to try some JHPs some day when the bullet situation improves.  The best group of ten shots at ten yards that I have got so far with the FMJ is 1.5".  That is with a two handed grip.  I don't have a rest to hold the gun to actually measure accurcy.

kobus

  • Guest
Re: Cartridge O.A.L.
« Reply #7 on: July 14, 2013, 12:54:35 PM »
i prefer to load slightly shorter COL than what my pistols' chamber can handle for a specific bullet. i believe that the extra seating depth and greater contact area allows for more stability of the bullet in the case.