Can you use standard loading data for cast boolits when shooting them with gas checks or do you have to reduce the load to account for the increased pressure? Is there some kind of formula to apply?
Thanks for your help!
Can you use standard loading data for cast boolits when shooting them with gas checks or do you have to reduce the load to account for the increased pressure? Is there some kind of formula to apply?
Thanks for your help!
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
Pretty sure Larry Gibson did a pressure test on checked vs plain base and found less pressure with checks.
8500' Wet Mountain Valley, Colorado
You could, up to 2500fps or so, but it's always wise to work up from a bit less than the listed values.
What specific chambering are you working with?
Chris
IF they are gas-checkable boolits the load books will have taken this into concideration.
1 you need to find the diamiter of your barrel (either slug the barrel or pound-cast the chamber) [use the search box at the upper right of this page]
2 you'll need to find the diamiter .001-.003 over the barrel size that works best for your gun
3 use the hardness (BHN) that's best for the speed you intend to push the boolit
4 look up load data, start with the lowest load and work your way up to where you get the best accuracy
No need to change loading data . The load listed for a gas check boolit can be used for a plain based boolit and vice versa ... all other things being equal of course .
If I remember correctly member Larry Gibson did some testing which revealed the gas checked boolit developed LESS pressure than plain based boolits !
Larry G. ...correct me if I'm wrong on this .
Gary
Certified Cajun
Proud Member of The Basket of Deplorables
" Let's Go Brandon !"
Gas checks produce less pressure due to controlling obturation.
Thanks guys. Great information. Just what I was looking for. Appreciate it.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
:There are 3 different loading levels for 45/70 for different strength firearms:
Lightest For 1873 Springfield
Medium For 1886 Winchester & 1895 Marlin
hotest For Ruger No 1 an No 3
You don't want to use load-data for a category above what your gun is rated for.
I'd suggest staying safe and sticking with the lowest category, it should achieve anything you want to do with that gun
I have not seen a need to GC 45/70 boolits even though I have GC molds
If you are not shooting a trapdoor you are likely to find your shoulder is more sensitive than the gun/barrel is! That is, you will want to stop before you reach any limitations of the gun.
Wayne the Shrink
There is no 'right' that requires me to work for you or you to work for me!
I have several loading manuals from both powder and boolit manufacturers. They all show loads for jacketed and cast boolits, but none of those manuals show loads specifically for cast boolits with gas checks. Unless I'm reading your responses incorrectly, any appropriate load for casts boolits (without gas checks) listed in these manuals will work for boolits with gas checks. Am I wrong? Thanks.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
If the load works with a plain based bullet, it will be fine with a gas checked bullet of similar design. Vice versa would work too, except, the limits you can push a plain based bullet with good accuracy and no leading is lower than it is with a gas check design.
So, yes, any apprpriate load from a manual for a plain based bullet will work fine with a gas checked bullet of similar weight and design.
The .45-70 with 405 grain lead alloy bullets is very well-plowed ground. You should be able to easily find load data for any design of bullet with any safe powder combination you want without having to try very hard. As stated, mind the level your rifle is and go from there, but I honestly never saw a need to go above Trapdoor levels in the .45-70.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
If you're a beginning reloader, just read a lot, ask a lot of questions and double check everything. Don't push the envelope. I have found there are two cartridges out there that really seem to attract guys who want to hotrod them and the .45-70 is #1 in that regard. Just have to shake my head, the .45-70 is powerful even when it's not.
In another thread that's going now, I and several others express that we like 12 grains of Unique as a load in .45-70 and it works beautifully, but I don't think you'll find it in modern load manuals, I got mine from an old Lyman. There's a lot of us on here who like fast powders and light charges and it works great, but there is always the danger of a double charge and 24 grains of Unique would make for a very bad day. I charge mine in a loading block and visually check all of them with a strong light and just the other day, that check caught a double charge and the one I missed that had no powder (wife came in and asked a question). Would have been a disaster if I didn't have that check my Dad ingrained in me for reloading. Everybody has a method, just make sure you do some kind of secondary check before seating a bullet.
Thank you for the information and for the advice. Much appreciated.
Hope you guys have plenty on hand cause Unique is out of stock everywhere.
Last edited by Dogbone13; 07-27-2020 at 01:06 PM.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
"Hope you guys have plenty on hand cause Unique is out of stock everywhere."
If they have it, Trail Boss works very well for light loads in the 45-70 as well. And no way to overcharge, so long as your not compressing the powder.
Chris
Thanks Chris.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
You normally would not need a gas check for the 45 70 unless you are using a Ruger No. 1. My Lyman manuals only list data for gas checked bullets for the Ruger. Shooting the 45 70 is much more enjoyable when kept below 1600'/sec.
NRA Benefactor Member NRA Golden Eagle
Again, thanks for the input/advice.
Everything we hear is an opinion, not a fact. Everything we see is a perspective, not the truth. NRA Life Member
BP | Bronze Point | IMR | Improved Military Rifle | PTD | Pointed |
BR | Bench Rest | M | Magnum | RN | Round Nose |
BT | Boat Tail | PL | Power-Lokt | SP | Soft Point |
C | Compressed Charge | PR | Primer | SPCL | Soft Point "Core-Lokt" |
HP | Hollow Point | PSPCL | Pointed Soft Point "Core Lokt" | C.O.L. | Cartridge Overall Length |
PSP | Pointed Soft Point | Spz | Spitzer Point | SBT | Spitzer Boat Tail |
LRN | Lead Round Nose | LWC | Lead Wad Cutter | LSWC | Lead Semi Wad Cutter |
GC | Gas Check |