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Type of bullets

I know the load books show specific name brand bullets for each load data. If the weight of the bullet is the same and the bullet is basically the same - flat nose, round nose, etc. what is the difference between the name brand and aftermarket bullets - bulk bullets ? I understand there may be length differences but they have put holes in plastic bottles, paper, wood, for several years now but I think I have been over thinking the of bullets and the seating depth in relation to pressure
any thoughts on this????

rhanks
 
I think I have been over thinking the of bullets and the seating depth in relation to pressure
any thoughts on this????

rhanks
Basically the same, maybe close, but still can get you into trouble. Take
two of the same styles, but different makers, and check the base to
ogive and see what you get. Same style, same weight may have one at
.050" thou of a jump, and the other may put you hard up into the lands
with some dangerous pressure. I've found same bullets, from the same
maker, but a different lot that needed a seating depth change.
 
You are not over thinking this in my opinion. Just because different brands of bullet have the same weight and the same alleged similar "nose" design or close to it doesn't mean anything in my experience.

For example, secant versus tangential ogives can make a huge difference in seating depth. Boat tail versus flat point is another issue affecting performance accuracy wise. Jacket thickness and internal construction can affect terminal performance. I could go on, but you get the point.

For example, the Sierra 85 BTHP in 6mm requires significantly deeper seating depth in some rifles, e.g. Tikka, Browning to chamber a round than another bullet with a same weight and similar designed nose.

In my experience, bullet selection is one of the most, if not the most important component in load development for obtaining desired accuracy and terminal performance. Also, since seating depth can affect pressure and functionality, this is also an important consideration. The first action I take when starting with a new bullet is measure the maximum COL in the specific rifle that I am loading. I use this data along with other parameters to select the starting seating depth for load development.
 
"In my experience, bullet selection is one of the most, if not the most important component in load development for obtaining desired accuracy and terminal performance."

I agree completely. I always approach load development from the terminal outcome desired first. A variety of powders can be used to drive a bullet, but knowing what the goal of the bullet's flight is about is the most critical. A for instance that comes to mind is that some premium hunting bullets do not necessarily transform into tack driving, target like hunting loads. They might for you, and that's good, but sometimes we have to settle for a hunting load that is confidently good enough that we can rely on it for accurate, humane kills on game at reasonable distances.
 
Seating depth and pressure. In most cartridges when a bullet is seated at less than or equal to the cartridge COAL changes in seating depth are not a significant factor in pressure in most factory rifles or in most custom rifles when chambered in standard SAAMI chambers. Where it becomes significant is when the bullet is seated near the point of the bullet ogive being very close to the rifling or jammed in the rifling. In this case the dynamics of the combustion and bullet movement change drastically and pressure can increase significantly. It can also become more significant if the bullet base begins to extend significantly below the shoulder-neck junction.

With custom chambers matched to specific bullets things get a little more complicated because of the relationship of the bullet ogive to the rifling.

As for bullets of different designs/shapes if seated to the same COAL the pressures will change since it is likely the case volume and bearing surface of the bullet will be different. Jacket hardness and thickness can also be different and affect the pressure.

Ultimately, you start your load workup low at a safe pressure level and work up until you reach the maximum charge, maximum velocity for the recommend bullet or you see pressure signs.
 
I have always stayed ion the low to middle of max load - for plinking - I am not trying to knock the paper off the wood backing - just putting holes in it - I don’t like pain, so will do everything I can to stay safe !!
 
As rabbitslayer illustrated, most of the reloading manuals lump all of their certain-weight bullets for a given caliber into the same powder start/max recommendations, regardless of flat-base, boattail, ogive, etc. While jacket thickness and amount of jacket contact with the bore are probably the two things that affect pressure variations the most, if I use a certain weight bullet as shown in the manuals that is of different manufacture, start at the BOTTOM of the recommended powder settings, I feel pretty safe in having worked up scores of such loads over the past 50+ years and have had no bad incidents over-pressure when starting out. Keep in mind this only applies to when using copper-jacketed, lead-core bullets. If using solid copper bullets, steel core or such other types of bullets, additional care and scrutiny should be applied - as well as ascertaining the load data in the manual isn't rifle-specific - such as for a bolt gun if you are using a semi-auto, etc.,

If you are just plinking, and not concerned with extreme accuracy, the "bulk" bullets can be fantastic deals as compared to the "premium" bullets. Interestingly, the bulk FMJ military-style of bullets that are so often sold in bulk actually often cost more than certain name-brand varmint bullets (like V-Max and Nosler Varmageddon, etc.) and USUALLY don't shoot NEARLY as well. I have bought bulk varmint bullets that cost as low as about $9.00/100 (look at those "Varmint Nightmare" bullets from Midsouth Shooters Supply, as an example). They shoot about 1/2" MOA in my rifles. While I have other loads with other bullets that do a lot better - sometimes I don't need better. Really cuts down the cost of shooting in these days of high prices for components. Shooting "seconds" can provide a lot of savings, though the quality of the seconds varies a LOT depending on where you buy them. Go to Midway, USA and click "Clearance" and hit tab "over 50% off". Midsouth Shooters Supply also usually has a selection, as does Shooters Pro Shop (all Nosler products). From my experiences, Shooters Pro Shop quality is the best of the "seconds", though their prices have really come up in recent times.
 
I try to measure bearing surface and use that as my qualifier for similar weight projectiles. A classic example is the Hornady .224 75gr Amax. The rule of thumb for Service Rifle shooters was 24gr of Varget or RL15 under any 75-77gr bullet except 75gr amax. It had its own load data due to increased bearing surface leading to much higher pressures.
 
Projectile length for the same weight pill can trip you up big time especially when restricted to mag length.

I was working up a 222 load and subbed 50gr Nosler BT for FB Hornady with the same charge.
Pressures instantly were excessive due to needing to seat the longer Nosler deeper upsetting the case volumetric efficiency.
Too bad the preferred Nosler BT didn't group in that 222 with that powder so back to the Hornady #2240 FB that shot 0.3" all day long.....
 
As rabbitslayer illustrated, most of the reloading manuals lump all of their certain-weight bullets for a given caliber into the same powder start/max recommendations, regardless of flat-base, boattail, ogive, etc. While jacket thickness and amount of jacket contact with the bore are probably the two things that affect pressure variations the most, if I use a certain weight bullet as shown in the manuals that is of different manufacture, start at the BOTTOM of the recommended powder settings, I feel pretty safe in having worked up scores of such loads over the past 50+ years and have had no bad incidents over-pressure when starting out. Keep in mind this only applies to when using copper-jacketed, lead-core bullets. If using solid copper bullets, steel core or such other types of bullets, additional care and scrutiny should be applied - as well as ascertaining the load data in the manual isn't rifle-specific - such as for a bolt gun if you are using a semi-auto, etc.,

If you are just plinking, and not concerned with extreme accuracy, the "bulk" bullets can be fantastic deals as compared to the "premium" bullets. Interestingly, the bulk FMJ military-style of bullets that are so often sold in bulk actually often cost more than certain name-brand varmint bullets (like V-Max and Nosler Varmageddon, etc.) and USUALLY don't shoot NEARLY as well. I have bought bulk varmint bullets that cost as low as about $9.00/100 (look at those "Varmint Nightmare" bullets from Midsouth Shooters Supply, as an example). They shoot about 1/2" MOA in my rifles. While I have other loads with other bullets that do a lot better - sometimes I don't need better. Really cuts down the cost of shooting in these days of high prices for components. Shooting "seconds" can provide a lot of savings, though the quality of the seconds varies a LOT depending on where you buy them. Go to Midway, USA and click "Clearance" and hit tab "over 50% off". Midsouth Shooters Supply also usually has a selection, as does Shooters Pro Shop (all Nosler products). From my experiences, Shooters Pro Shop quality is the best of the "seconds", though their prices have really come up in recent times.
I get a lot of my bullets from Everglades or US Reloading - and do have some name brands - Berry, Nosler, Speer - just plinking and enjoying
 
If you want/need or wish to mix bullets(brands) in loads by weight, I would use a bullet comparator so you can measure the (cbto)cartridge base to ogive (an easily measured spot on a bullet) length. You could than, using published load data, mix brands of similar weight and construction (jacketed/leadcore) bullets for plinking, blasting or shtf ammo. I do this with AR ammo, although expect point of impact to change when bullet type or brand changes. Overall length may change but you can maintain a cartridge base to ogive length that the rifle likes.
 
If you want/need or wish to mix bullets(brands) in loads by weight, I would use a bullet comparator so you can measure the (cbto)cartridge base to ogive (an easily measured spot on a bullet) length. You could than, using published load data, mix brands of similar weight and construction (jacketed/leadcore) bullets for plinking, blasting or shtf ammo. I do this with AR ammo, although expect point of impact to change when bullet type or brand changes. Overall length may change but you can maintain a cartridge base to ogive length that the rifle likes.
Understand - can start doing that and makes good sense - thank you
 

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