Bullet over all length question

[thelurker]

I have searched high and low and cannot find this info.

With regard to 9mm ammunition, are there any differences between 147, 124 and 115 in their overall length? I was having some failure to feed issues with 147 gn ammo and was considering 124 as an alternative. What I don't know is how does the weight reduction affect the dimensions of the total round.

Would going to a 124 grain bullet possibly help with my FTF problem?

Thanks!

[Jumping Frog]

Not necessarily. It is the same SAAMI maximum length for a cartridge regardless of bullet weight.

Changing to a different brand or profile may help feeding problems. Or it may not. It is very unpredictable.

Is this handloaded ammo you are talking about, or commercial ammo? Have you field stripped your gun and dropped the round into your chamber to make sure it chambers correctly?

Where does the feed get hung up?

[thelurker]

Not necessarily. It is the same SAAMI maximum length for a cartridge regardless of bullet weight.

Changing to a different brand or profile may help feeding problems. Or it may not. It is very unpredictable.

Is this handloaded ammo you are talking about, or commercial ammo? Have you field stripped your gun and dropped the round into your chamber to make sure it chambers correctly?

Where does the feed get hung up?

I'm shooting Federal HST 147 grn out of a PM9. It gets hung up on the feed ramp as the slide tries to chamber the next round. It broke in nicely with FMJ ammo, but the HP rounds seem to struggle a bit. I'm putting in another order of ammo and was thinking about ordering a couple boxes of 124 grn to see if it made any difference, but I'd rather shoot 147's instead if the dimensions are the same.

[Zylo_X]

Of course, first thing to check is your owner's manual.

Assuming no mechanical failure other than just excess dirt, I've never had a persistent problem with any type of ammo in my Taurus PT 92, 917 and Ruger SR9C. I routinely shoot 115 FMJ & HP, 124/NATO FMJ & HP, and 147 HP. At the moment, I'm out of 124 FMJ, but just giving them an eye balling with a level across the tops, here's what I see... In descending order, the 115FMJ is the tallest, then 147 HP, then 115 HP and 124 HP last. The HPs are thicker since they are not as tapered as the FMJ. I'm still 'testing' to see which works best with what, trying different brands, etc. Would like your feedback on what you're shooting and what its doing.
Hope this helps.

[Texas Dan Mosby]

I'm shooting Federal HST 147 grn out of a PM9.

If I am understanding this correctly, you are shooting factory ammo, and IMO, OAL of a factory round would be one of the last things contributing to feeding problems.

It broke in nicely with FMJ ammo, but the HP rounds seem to struggle a bit.

Compare the HP bullet profile with the hardball your gun shoots well. Some HP's, like the remi golden sabres, have profiles very similar to hardball, and run well in most guns, others...not so much. Check out a forum dedicated to your gun and see if you can find a trend in any one particular HP round that seems to run well in your gun and try that.

Remember that there is NOTHING wrong with sticking with hardball, as THE most important factor when it comes to ammo is that it MUST be able to reliably run in your gun.

[thelurker]

I'm shooting Federal HST 147 grn out of a PM9.

If I am understanding this correctly, you are shooting factory ammo, and IMO, OAL of a factory round would be one of the last things contributing to feeding problems.

Correct, and that is my question. I'm trying to determine if there are any variations in dimensions between caliber weights that might contribute to my problem, and could the same brand ammo in a different weight affect the way a round cycles through the same firearm.

My thoughts are that if one bullet weighs 147 grains and another weighs 124 grains, then the bullet should be smaller in some way. Maybe its just not seated into the casing as much.

Maybe this is a crazy question, but having never reloaded I'm just not sure.

[Middle Age Russ]

As others have said...
1) Maximum overall length of the cartridge should be the same regardless of the weight of the bullet. Factory ammo does not typically exceed the published maximum length since it would indeed cause feeding or perhaps other issues with firearms it is used in.
2) The nose profile of the bullet is the likely cause of your feeding issues. Changing to a lighter bullet of the same design will not likely result in fewer feeding issues. Some profiles are more "forgiving" and feed about as well as hardball (FMJ) in just about all firearms. Other profiles can cause issues with certain feed geometries.

[MoJo]

The difference between 115, 124, and 147 grain ammo is the depth the heel of the bullet goes into the case. The 147 is the longest bullet therefore it goes further into the case than the others. Cartrage liength is very close to the same between the three bullets. Try different bullet weights and different brands of ammo. As mentioned earlier Remington Golden Saber has a very pronounced round profile thus with enhanced feed reliability.

[thelurker]

The difference between 115, 124, and 147 grain ammo is the depth the heel of the bullet goes into the case. The 147 is the longest bullet therefore it goes further into the case than the others. Cartrage liength is very close to the same between the three bullets. Try different bullet weights and different brands of ammo. As mentioned earlier Remington Golden Saber has a very pronounced round profile thus with enhanced feed reliability.

Thanks for the clarification. I suspected the bullet may be pressed further into the casing, but wanted to make sure. Fortunately, I've been lucky enough with my guns that I've never really had any problems with them feeding any brand or weight ammo I've used.

[iratollah]

OAL for 9mm shouldn't really change. The only way to make a bullet heavier is to make it longer as diameter remains the same. So you'll be seating deeper and of course your load will change.

We change OAL in .223 with the 80gr bullet, but that's a longer than magazine length round anyway and is fired single shot through the AR using a follower stop in the magazine.