Precision Delta 9mm fmj vs fmj-tc [Archive] - Glock Talk

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wjmiller3
01-19-2012, 14:46
Done the searches and cant find anything on topic. I have a 34 and will be ordering some 147gr from precision delta shortly. Just wondering the pro/con of truncated cone vs normal fmj? It will be used only for paper and steel at IDPA matches.

fredj338
01-19-2012, 15:49
Mostly it's a bullet length/fit issue. A RNFMJ will be longer than a TCFMJ. I think the TC are slightly more accurate, but I haven't done a ton of testing to confirm that.

wjmiller3
01-19-2012, 19:32
So has anybody ever had any reliability problems out of 147gr fmj-tc in 9mm? All I ever shot in my .40 was truncated, but I have never seen anyone else using them in 9mm's. All things being equal I would like to shoot the 147 fmj-tc's, but not if reliability suffers. It's a gen4 34 if it matters.

NG VI
01-19-2012, 21:26
I doubt they'll be any less reliable in any decent quality, modern pistol. G34 especially.

And the reason the .40s are all either truncated, even the 'rounder' of them, is because the bullet needs to be a certain weight and remain in the right overall length class, the truncated cone allows for more case room to be allotted to powder and not an excessively long bullet.

WiskyT
01-19-2012, 21:46
I doubt they'll be any less reliable in any decent quality, modern pistol. G34 especially.

And the reason the .40s are all either truncated, even the 'rounder' of them, is because the bullet needs to be a certain weight and remain in the right overall length class, the truncated cone allows for more case room to be allotted to powder and not an excessively long bullet.

I see it as the opposite. When they truncate the bullet, they have to stick the weight they cut off on the base of the bullet, which makes it intrude further into the case.

The TC bullets should feed fine. Think of them as a hollow point with the hollow filled in.

As far as accuracy, I doubt you could find a difference in a Glock. The only way to know for sure is to try them out and compare.

NG VI
01-19-2012, 22:24
Well if the two loads have the same overall length, a truncated cone bullet is shaped more like a cylinder than the roundnose is, and so the truncated cone can be shorter for a given mass.

WiskyT
01-19-2012, 22:28
Well if the two loads have the same overall length, a truncated cone bullet is shaped more like a cylinder than the roundnose is, and so the truncated cone can be shorter for a given mass.

Yes, but TC's are typically loaded to a shorter OAL because they will contact the rifling if seated as long as a RN.

The 40SW was designed around HP, not TC. A TC is just a HP with the hollow filled in.

wjmiller3
01-19-2012, 22:45
I agree with both of the last two posts. At least that is how I have always looked at it. So I think here before I go to bed for the night I will order 1k of the truncated and see how they do.

NG VI
01-19-2012, 23:28
I see, makes sense.

WiskyT
01-20-2012, 18:59
I see, makes sense.

I should say I was speaking generally of TC and RN bullets. I'm sure there are some stubby RN bullets and long pointy TC bullets that would support your point too.