col/oal pistol cartridge

riderrick

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so loading 230g rn 45 acp. with 700x powder the oal in lymans 1.275, with hs6 hornady wants a 1.23 col (numbers are from memory). shooting these loads 2 of 3 45's put the shorter rounds all over the place. what would happen if i loaded the hs6 to the 700x legnth? is it the legnth that caused the spread?
 
I would say that its more like your bullet velocity that is causing your spread...
What i would do is to pick a OAL. Myself i would pick the longest OAL that reliably functions in the gun and mags...
If 1.275 works just stick with it...I myself use 1.280 for .45 230 gr RN..

Then pick one powder... and work to get a load that works to the accuracy you want...
700X is a faster burning powder than HS6.. so the longer OAL is better to keep the pressures down...
Which will work for HS6 as well... You will just need to determined the amount of powder that
safely gives you the velocity that gives you the accuracy you need..


Always work from a known load and work up with your powder in small increments...to get the desired results...
Load 5 of each and test fire them at a target and preferably over a crony to give you FPS ...

Always look for signs of pressure like flattened primers etc.... when you are developing your loads...
If you see flattened primers your pressure is getting too high and you need to reduce your powder...
or switch to another powder.. Slower burning powders are better for keeping pressure from spiking ...

Good Luck

RDG
 
Oal is different in every gun, if really needed seat a bullet in an empty case and see if it hits the lands. back it off .020 after it doesnt(works the best)
 
thanks for the help RDG. I just started reloading and was wondering if straying from spec would be a no-no. I am a mechanic and straying from specs while engine building would be very detrimental to the end product. i will play and see what happens
 
thanks for the help RDG. I just started reloading and was wondering if straying from spec would be a no-no. I am a mechanic and straying from specs while engine building would be very detrimental to the end product. i will play and see what happens
I'm a new reloader and was worried about the exact same thing. I was loading .45 ACP with Berry's 230gn TMJ RN bullets and Titegroup powder. So what I did was load up twenty each, all with same powder load, with OAL's of 1.250-1.259, 1.260-1.269 and 1.270-1.279. I arranged them in a storage box with notes of which were which and went to the range. Shot each size through two different 1911's (SR1911 and S.A.M.) and my Glock 21SF. Final results: No differences whatsoever. All fed perfectly through all three guns (actually better than Norinco factory ammo - had a few minor feeding jams with that stuff in the 1911s). Stay in the 1.250" (minimum is 1.20") to 1.270" (maximum is 1.275") range and you'll be fine. I actually aim for around the 1.265" range - same as the factory ammo I measured, which varies considerably from round to round.

The manuals talk about higher pressures with shorter OALs, but I don't think it's enough to ever notice without a chronograph. I sure couldn't tell the difference anyway.
 
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I'm a new reloader and was worried about the exact same thing. I was loading .45 ACP with Berry's 230gn TMJ RN bullets and Titegroup powder. So what I did was load up twenty each, all with same powder load, with OAL's of 1.250-1.259, 1.260-1.269 and 1.270-1.279. I arranged them in a storage box with notes of which were which and went to the range. Shot each size through two different 1911's (SR1911 and S.A.M.) and my Glock 21SF. Final results: No differences whatsoever. All fed perfectly through all three guns (actually better than Norinco factory ammo - had a few minor feeding jams with that stuff in the 1911s). Stay in the 1.25" (minimum is 1.20") to 1.270" (maximum is 1.275") range and you'll be fine. I actually aim for around the 1.265" range - same as the factory ammo I measured, which varies considerably from round to round.

The manuals talk about higher pressures with shorter OALs, but I don't think it's enough to ever notice without a chronograph. I sure couldn't tell the difference anyway.

so with all the different lengths there was no difference in poi?
 
so with all the different lengths there was no difference in poi?
Heh :):redface::) I'm not a good enough shot to notice any differences in accuracy. Next time up I may sit down with a rest and really do some careful testing.

But really, I think the OAL thing is going to mostly affect feeding rather than accuracy (but what do I know? I'm a newb still :)). Like I said, the pressure differences aren't noticeable at all in shooting feel.

Next time I go I will load up a range of different powder loads (all same OAL) for my accuracy testing. That may show up some differences in accuracy. Last trip I tested some different loads just for feel, and I could definitely tell the difference between them. Factory ammo feels pretty much like the max loads (Lyman book) I made. Minimum loads are soft, and many of the ejects landed right next to me in my range box. :D
 
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Barrel harmonics can do funny things. In the 44-40 thread I'm running here, I'm seeing groups more all around the paper with different powders, and charges. My hunting load is dead center, but most of the experimental loads have been left of center, and low, but an occasional one is right of center. for a ten shot group. Even had some right off the paper. Group siszed varied widely too, but in general, at least so far, slower = tighter, with few exceptions.
 
thanks for the help RDG. I just started reloading and was wondering if straying from spec would be a no-no. I am a mechanic and straying from specs while engine building would be very detrimental to the end product. i will play and see what happens

You are welcome...

One thing i did not mention was tuning your OAL to your specific barrel..
If you have one gun.. then its easy..
Just take out the barrel.. make a dummy round at a long OAL.. Lets check it in the barrel

As mentioned by LeadLoader.. I usually do this for all my pistols..
Determine the OAL that touches the lands of the rifling... then set it back
10 thou.. or so... That will set my OAL for that barrel...

Then i work to get the correct load to give me the desired accuracy..as mentioned in my previous post..

RDG
 
Like I said, the pressure differences aren't noticeable at all in shooting feel.

Hey there futz...

The pressure i am talking about is the internal pressure of the round... (CUP)
which can spike and cause catastrophic failure of the
pistol and to the shooter as well..

You really can't feel the difference, it but it can be measured with specialized gear...
That is why staying within the reloading manual specs is important...

You can detect signs of pressure getting too high by looking
at the primers after shooting.. If they are severely flattened
you are probably walking in danger zone...
When i see things like this i back off with my powder..

Good Reloadig everyone!!!!

RDG
 
IMO the difference in OAL is too small to be a factor. However, If you are concerned, why not just drop the load 10% and work it up. Sometimes differences in OAL are due to feeding issues. The manufacturer wanting it to feed in all possible firearms, and fit in all possible mags.

In your case however, I'm going to say that Lyman is probably quoting the SAAMI OAL, and changes as required for a generalized bullet shape to feed, and Hornady is using what they have determined is best for their own Hornady branded bullet to feed and work best in all possible firearms.
 
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One comment I saw above about pressure and OAL. For a given powder charge, if you decrease the internal volume (shorten OAL), pressure increases very rapidly, especially with fast burning powder. The pressure increases MUCH quicker than you expect for what is seemingly a minor decrease in OAL. Increasing OAL always decreases peak pressure.

I posted a couple links on the the thread about bullet slipping. http://www.canadiangunnutz.com/forum/showthread.php?867556-bullet-slip

In a 9mm, changing nothing except seating the bullet deeper by 0.15", raises peak pressure by almost 300%. Note that proof loads are 130% of normal pressure.

You can't "feel" peak pressure. The peak pressure doesn't substantially change the velocity, because it is of short duration. In handgun cartridges, peak pressure occurs within the first 1/4" of bullet travel, maybe a bit later in a large cartridge with slow burning powder.
 
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The pressure i am talking about is the internal pressure of the round... (CUP) which can spike and cause catastrophic failure of the pistol and to the shooter as well..

You really can't feel the difference, it but it can be measured with specialized gear... That is why staying within the reloading manual specs is important...

One comment I saw above about pressure and OAL. For a given powder charge, if you decrease the internal volume (shorten OAL), pressure increases very rapidly, especially with fast burning powder. The pressure increases MUCH quicker than you expect for what is seemingly a minor decrease in OAL. Increasing OAL always decreases peak pressure.

...

You can't "feel" peak pressure. The peak pressure doesn't substantially change the velocity, because it is of short duration. In handgun cartridges, peak pressure occurs within the first 1/4" of bullet travel, maybe a bit later in a large cartridge with slow burning powder.
Good to know. Thanks for the good explanations guys.
 
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