diff in CMJ and FMJ

hoochie

hoochie

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are CMJ's weaker than a FMJ?
the FMJ has a thicker wall?
Theres some misunderstanding between me and a few other people.. so I shoot this question out to you guys for clarification.
thanks.
 
CMJ's start with your fully formed standard cast or swaged lead bullet, it's then entirely copper plated with a very thin coat, there is no exposed lead visable.
FMJ's start with a heavier thicker copper jacket, and lead is swaged into the opening. The base will be exposed lead.
 
oK different manuafacturers have different methods...
jacketing and plating are very different...

for montana gold... a CMJ and FMJ start with a lead core.. the (CMJ is a pinch lighter)
the CMJ is swaged into a cup for the base and then swaged into a jacket so there is no exposed lead...
the FMJ is swaged into a jacket and the closed the base is exposed lead...
 
Clipboard01.jpg

FMJ on the left (Montana Gold I think) and 2 brands of CMJ (Frontier and BDX, in that order)

(E) :cool:
 
I can assure you that the one on the left is a Montana Gold FMJ as you stated, but the one on the far right is in fact an Xtreme, formerly WestCoast as BDX is the distributor for these products. They do not have their own brand at this time. As a side note, the Xtreme are excellent choices for a plated bullet as they ar slightly thicker in plating and post swaged to size amking them far more consistent than a copper washed or regular plated bullet.
Cheers:)
dB
 
(((Echo))) said:
FMJ on the left (Montana Gold I think) and 2 brands of CMJ (Frontier and BDX, in that order)

(E) :cool:
Click to expand...

The one on the left is a CMJ. If it were an FMJ, the base would be exposed lead. Montana Gold's come in both flavours.

And per the other guys, the one on the right is an Xtreme (from BDX). Great bullets.
 
I beg t0 differ. I think you will find the one on the left to be FMJ, full metal jacket, having the exposed base. CMJ is complete metal jacket, covering the base as well.
Cheers
dB
 
Left one is FMJ(my picture......the FMJ does have lead exposed. next is a CMJ next a IFP and finally a JHP....

DSC00080.jpg
 
Last edited:
I sit corrected! A thousand apologies to acrash. In my response earlier I stated that the one on the left was a FMJ because of the exposed base, but failed to look close enough to see that the supposed exposed base was in fact a copper shield or plug. Thats what i get for not looking closer. The later photo subsequently shows the difference in a much clearer manner.
I bow in the presence of greatness....;)
dB:)
 
ok,so next question....
why a CMJ or FMJ for shooting? advantages?

I either shoot FMJ or JHP.. I honestly hadnt even heard of CMJ till last week.
just want to know what the difference in performance is, if any, or why one would be chosen over another.. different applications or terminal ballistics?
I see that CMJ's are cheaper.. but why?
 
You mean the FMJ are cheaper ;) ........the CMJ have no lead exposed and lead at the base will end up in the compensateur, which is hard to remove. Perhaps ballisticaly.....????? but I wouldn't know......
 
no.. I meant that CMJ's seem to be cheaper.
In another thread in this section, a guy said that he bought 2000rounds for $134 ( $68 per 1000)
I've been paying $76 per 1000 FMJ and $80 JHP per 1000 from a local store.

the back of my FMJ's have a concave portion of lead exposed ( i thought it had something to do with helping it fly better, and my JHP's are flat based.
I like the JHP's for the "fun factor" when shooting water jugs etc, but I am really just trying to find the cheapest "paper punching" rounds that are not lead cast.
 
CMJs are cheaper simply because it's an easier method of producing "FMJ-like" bullets; instead of having to stamp out the cores and jackets separately, and then swaging them together (sometimes in the same machine, but still separately), CMJs are produced by swaging out cores that are ALMOST to the right diameter, then running them through an electroplating fluid/process on a conveyor belt, so they're plated with copper when they come out at the other end. The enclosed base FMJs in the first photo have to add yet ANOTHER step to the FMJ manufacturing process, by stamping a base cup onto the core before the true jacket is added.
 
OK GUYS;
The main reason for CMJs is the fact that many facilities have limited air born lead on their indoor ranges....
Many ranges will not let you fire anything but CMJs and leadless primers....
This is the future....
John
 
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