I'm looking at reload data for 7.62x39, and it lists different data for 123 grain and 125 grain fmj bullets. Does two grains in bullet weight really make that much of a difference? Say i have a powder that's on the list of 125 gr, But i only have 123 gr bullets on hand. Is there a safe way to work up a load?
2 grain difference in bullet weight, completely different load data?
- Thread starter Bushbum40
- Start date
Me, I'd not bat an eye using a load published for either weight bullet with the other, at only two grains weight difference for the bullets.
Standard rules apply. Start a bit lower, work up to see what it does in YOUR gun.
Cheers
Trev
Standard rules apply. Start a bit lower, work up to see what it does in YOUR gun.
Cheers
Trev
The 2 grain difference in weight will have virtually no effect on the pressures developed.
However, The bearing surface and diameter may.
It is always a good idea to work up from a couple of grains of powder below to be sure
the other bullet will be OK with the same charges.
I have used identical loads with both 165 and 168 grain 30 cal bullets safely & successfully.
Personally, I would measure diameters with a good vernier micrometer to be sure one bullet is
not too much different in diameter. again, it's a judgment call, but .0005" is unlikely to put you
into the danger zone.
Regards, Dave
You can use the heavy 125 grain load data for the lighter 123 grain bullets safely. BUT even safer is to make up a workup load starting at the suggested starting load and work up look for signs of over pressure.
Reloading data is always "ball park" information because of variations in firearms and reloading components.
Reloading data is always "ball park" information because of variations in firearms and reloading components.
This is from Hodgdon's website, it echoes more or less what the more experienced folks are saying. I used this when looking up data for plated bullets. Reinforces the safety principle of starting low-mild and working up safely. Kind of like, "Never point a gun at something you are not willing to destroy" and the other principles that follow.
From http://www.hodgdonreloading.com/rel...a-do-i-use-when-my-specific-bullet-not-listed
"Current rifle bullets are constructed with a jacket/lead core or single material (such as all-copper). Bullets with lead cores typically display lower pressures than bullets of all copper or gilding metal structure. As such, we show data for both style bullets in a given weight, as often as possible. For example, should you have a Hornady GMX solid core hunting bullet, but our data for that weight bullet only shows a Speer lead core bullet and a Barnes all copper TSX bullet, use the data for the Barnes bullet. The GMX and TSX bullets being of similar metals and shape, can utilize the same data.
Pistol bullets create the same situation, having even more changes in shape and type. There are lead bullets, copper plated lead bullets, copper-jacketed lead core bullets, and frangible bullets. Frangible bullets are unique such that we always show separate data for them (and recommend not using any other bullet type data).
Lead bullets and copper plated lead bullets yield very similar pressure and velocity results, so when the weights are the same, the same data may be used for each. Jacketed Lead core bullets come in a variety of configurations. Jacketed Hollow points and Jacketed Flat points of the same weight use the same data. Round nosed, lead core, full metal jacketed bullets of the same weight can also use the same data.
In conclusion, bullets with similar shapes and construction materials will utilize the same data. And, above all else, work up your loads by starting with the beginning load and increase charges in small increments, at all times watching for case head pressure signs and stiff extraction."
From http://www.hodgdonreloading.com/rel...a-do-i-use-when-my-specific-bullet-not-listed
"Current rifle bullets are constructed with a jacket/lead core or single material (such as all-copper). Bullets with lead cores typically display lower pressures than bullets of all copper or gilding metal structure. As such, we show data for both style bullets in a given weight, as often as possible. For example, should you have a Hornady GMX solid core hunting bullet, but our data for that weight bullet only shows a Speer lead core bullet and a Barnes all copper TSX bullet, use the data for the Barnes bullet. The GMX and TSX bullets being of similar metals and shape, can utilize the same data.
Pistol bullets create the same situation, having even more changes in shape and type. There are lead bullets, copper plated lead bullets, copper-jacketed lead core bullets, and frangible bullets. Frangible bullets are unique such that we always show separate data for them (and recommend not using any other bullet type data).
Lead bullets and copper plated lead bullets yield very similar pressure and velocity results, so when the weights are the same, the same data may be used for each. Jacketed Lead core bullets come in a variety of configurations. Jacketed Hollow points and Jacketed Flat points of the same weight use the same data. Round nosed, lead core, full metal jacketed bullets of the same weight can also use the same data.
In conclusion, bullets with similar shapes and construction materials will utilize the same data. And, above all else, work up your loads by starting with the beginning load and increase charges in small increments, at all times watching for case head pressure signs and stiff extraction."
