Questions about OAL vs Factory ammo

[Varminterror]

if loaded to minimum Sammi spect to replicate factory compatability

There isn't a SAAMI minimum spec for specific bullets, so you really can't do so.

 

[TacticalBacon]

There isn't a SAAMI minimum spec for specific bullets, so you really can't do so.

Is this not the min OAL no smart A$$ intended

 

[Soonerpesek]

Oh well don’t mean to hijack someone else’s thread.

The thread is about OAL, so not highjacked.
The space in the case from the base of the bullet and the powder is the consistency provided the charge is the same.
Seating with your micro stem on the ogive is getting that space more consistent than seating on the tip, so the ignition and whatever accuracy the load provides is going to be more consistent .
There may be a variance in OAL with a more economical bullet, but the consistency of that same powder space will make up for that…IMO…


Did I write consistent enough….??

 

[Varminterror]

View attachment 1141799

Is this not the min OAL no smart A$$ intended

Which particular brand and model bullet will be appropriately seated at that length?

 

[Okie_Poke]

So my question is now

if loaded to minimum Sammi spect to replicate factory compatability would i then need to back off my charge as im seating the bullet closer to the powder ?

By that logic i would be off grid so to speak or no long following safe book value?

Or are those starting charge weights accounting for the entire spectrum of sammi min and max coal

I ask because i notice in lee reloading manual there is a Min OAL for each charge which i assume mean going below the OAL makes that charge no longer safe by their calculations

I may be in the minority here, and I don't have the technical background a lot of folks on here do, but I think you're overcomplicating this. If your goal is to load ammo that works in every firearm you have for that chambering, you are necessarily not able to optimize for peak accuracy. That is fine. You may or may not exceed the accuracy of factory ammo, but you can develop a safe load and reasonably accurate load that will function in all of your firearms. My guess is that with proper load development and reloading process you can still beat factory ammo, particularly if you're comparing your handloads to "plinking" grade factory ammo (and not match or premium ammo).

I have never studied a SAMMI drawing when determining how to setup my dies for reloading any cartridge. Every bullet shape is different, so I wouldn't know what to do with the SAMMI drawings even if I looked at them. I'm sure someone does know, but I don't. I recommend you do one (or maybe both) of two things to determine what COAL to use: (1) if you have a manual from the manufacturer of the bullet you are using, use the COAL listed in that manual for that bullet in your cartridge. It will probably work; they listed it for a reason. This will not necessarily work reliably if you are using a manual for Company A and bullets form Company B, however (again, the bullets are shaped differently). (2) As was suggested by someone else earlier in the thread, measure the COAL or CBTO of the bullets you are using in each of the firearms you are loading for, and then load so it fits in the tightest chamber. There are several ways of measuring this and several threads on the topic. If you don't have a manual from the company making your bullet, or they don't list a bullet-specific COAL for some reason, you'll have to use option 2. Even if I have the manual, I'd probably do option 2 anyway just to be safe and compare to what the book says.

With respect to the powder charge, I think you are safe to start a the minimum charge listed in the manual for the bullet you are using. If you don't have the manual for the bullet you are using, and even if you do, it's worth verifying the starting and maximum charges for a given powder and bullet weight and type across at least two sources. Start low (but not too low) and work up. When developing a round for multiple firearms of the same cartridge, I typically do my load development in the tightest chamber, stay off of the max charge, and test the load in all of my firearms before I deem it safe and load a bunch. I've never started with a powder charge below the starting charge listed in a manual.


With respect to "accuracy nodes," I think chasing something like that is a fool's errand if you're loading for multiple firearms, particularly if they are production guns and this is basic plinking or hunting ammo. Find a bullet/powder combination that shoots reasonably well in all of your firearms, and then load for reliability. I think your component selection and reloading practice will determine whether the round is consistently accurate more than trying to vary seating depth or powder charge to find a "node." It's still possible to work up a load tuning powder charge and seating depth to a degree when you're loading for multiple firearms, but you don't have the same flexibility you have when only loading for one, and you have to prove the load in multiple firearms. Again, the apparent object here is reloading good ammo for multiple firearms, not the absolute best ammo for a single match rifle. Different objectives, different methods.

 

[Akula69]

Disclaimer: I am anal retentive, and I know it.

Having said that, I touch my rounds 9 times before they go into the storage box. I handle the cases to de-prime (1), clean (2), sort by head stamp and bake (3), weigh and sort by case weight (4), load into the case feeder (5), actually load (6), measure for COAL (7), Drop into the Wilson round gauge (8), and weigh for overall weight (9) (which explains why I weigh and sort the cases by weight).

I do this to get the best performing case/projectile combination I can. I don't really load "range plinking" rounds - I try to get the closest consistency round-to-round that I can. Are they match grade? Not really, but damn close. Will they consistently chamber? Absolutely. Will it make a difference to the random home invader? Nope, but they will die from a clean, accurate MOA.

 

[NMexJim]

As Varminterror said, there are no SAAMI specs for bullets: and therefore if one assumes that that they are alike, then you’re courting problems. If you buy only one bullet profile by one manufacturer, then you should be able to load for all similar firearms provided you follow the bullet manufacturer’s suggested COAL.

For instance, I load 9mm for members of my family. There are a dozen 9mm involved. By using the manufacturer’s load data including OAL, then we’ve not had an issue. If I start to play around with length, then I can be assured I’ll see a problem crop up especially going long.

If you begin to assume that all 115 grain FMJ bullets will seat the same regardless of manufacturer, then you will have a chambering problem at some point. It might be years coming, but it will come. Mostly this has to do with shank length.

When you start changing profiles, i.e. FMJ, flat point, hollow point, etc, and don’t pay attention to OAL as well as ogive, those problems will come quickly.

Cartridge gauges work well as does the “plunk” test in the case of handguns or using OAL gauges and dye for rifle.

Regardless, you need to have a method and know what works in your guns. Keeping records helps quite a bit.

There have to be tolerances in any manufacturing operation. Henry Ford a prime example - replaceable parts. But you can reduce those tolerances and do it fairly easily with hand loading. Can you make a 1 MOA gun into a 1/2 MOA? Well, that takes us back to time and money. That’s the pleasurable part of all this. Working through the learning curve until you have an understanding of how changes could and will effect your ammo.

 

[CQB45ACP]

Exactly. Take a box of factory ammo and your micrometer and measure the COL. Every single factory round will be less then SAAMI minimums. In fact, I was loading some G2 projectiles from Speer, and took a box of 9MM Speer-loaded G2 and measured them - most were way below 1.100 (some down to 1.080) and none were consistent. You can do much better with your own rounds...consistency and the replication thereof being top on the list.

I just did this with 45acp Remington & Federal.

Six Federals ranged from 1.2625-1.2655

Six Remingtons from 1.253-1.2575

Pretty wide range.