45-70 conversion with N110

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I've got a CVA Hunter 45-70 conversion with Arrowheads LRMP and I plan to be shooting 40cal 225gr Pittman Accumax bullets with the HLB sabots. I just found a pound of N110 powder. Any thoughts on what the max load would be for that and what kind of velocity? Will I likely need to use a felt or wool wad and if so, which one? I'm shooting 59gr of H4198 now and all's good but it is a bit temp sensitive about 3fps per degree. I'm getting 2460fps at 35 degrees currently. Thanks.
 
After about 35gr of N110 you will start blowing sabots. Even 35gr is very rough on them. That is with a 200gr bullet.
 
Pressure is plenty safe. Its the pressure and how fast it rises that makes it rough on the sabots. A wad does help.

Over 2400fps IIRC and it a very very temp stable load.
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I've got a CVA Hunter 45-70 conversion with Arrowheads LRMP and I plan to be shooting 40cal 225gr Pittman Accumax bullets with the HLB sabots. I just found a pound of N110 powder. Any thoughts on what the max load would be for that and what kind of velocity? Will I likely need to use a felt or wool wad and if so, which one? I'm shooting 59gr of H4198 now and all's good but it is a bit temp sensitive about 3fps per degree. I'm getting 2460fps at 35 degrees currently. Thanks.
I use the Pittman Accumax 253 grain sized to .4505" with 60.5 grains of H4198. I haven't noticed that much change in velocity caused by temperature. I have used a number of powders with my Hankins rifle but have not tried N110. I'm super consistent with H4198 and plan to stay with it. Have you tried .451 or .452 bullets sized to your barrel bore?
 
In a conversion, which has a chamber, you must fill the chamber and the bullet cannot be in the camber at all or you will get flame cutting beginning at the rifled part of your barrel. N110 does not give a long enough powder column with most breechplugs. If you have a borescope load your powder and a wad and then borescope it to see if your load is completely filling the chamber/45-70 casing area, if it does you are good if not use a powder that will have a longer column. I know this after shooting 1-1/2lbs. of N110 in an Apex and ruining the barrel. It shot really good but when I bought a borescope and could see the damage I was bummed. A barrel without an existing chamber is no issue but conversions beware. Just my (BAD) experience. So to the OP I would suggest against N110 in a conversion.
 
Wow D55, that issue was never even on my radar. I will certainly have to do some contemplation on that. I don't have a borescope, wish I did.

Hairybird, I don't have a sizing die and I would prefer to use lighter bullets so I'm trying to stay away from the bore size bullets. With my current setup I sight in at 35 degrees so I won't be too far off from 20 degrees to 50 degrees. If it gets much warmer or colder then you have to start compensating when you get out past 200 yards. I've done a pretty fair bit of shooting over the chrono at different temps and 3fps/degrees is about what I'm getting.
 
Just a consideration. You could put some farina/cream of wheat as a filler on top of the N110 charge then a wad or if using a sabot you may not need one. They did this in cartridge guns for reduced loads. It is an option if you absolutely can't find powder. Also there are some decent borescopes out there for under $100 that will serve your purpose. Hope this info helps you and others to not ruin a barrel like I did.:( I do not have any idea of what fouling with a filler like this would be like but I know powder doesn't get any cleaner burning than N110. IME
 
I agree and I have the Teslong. They reveal what you cannot otherwise see. I admit when I (SCREW UP) and wish the cost of a rifle to a mistake on no-one hope all who have conversions and shoot smokeless see this for what it is , a WARNING. BE SURE YOUR POWDER COLUMN FILLS THE CHAMBER AREA ON CONVERSION BARRELS!!!
 
If you have some SR4759 you might want to see how its powder column compares. I think its bulkier than N110 and you can use a little more before the sabots start stressing. 38-39gr of 4759 was no problem for me as far as sabots and the speed is good. Use it sparingly though because its no longer made.

Compare the 2 with the Lee Dipper chart. You need a larger dipper for the 4759
https://leeprecision.com/files/instruct/Dippers.pdf
4759 3.4=34.2gr
N110 2.8=33.6gr A 3.4 would put it at over 40gr.
 
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With the Arrowhead plug, qwakattak, you may be OK as I believe Luke's plugs are about 1-1/2" from the shoulder inside the chamber and mine which is a DI by Hank is only 1" from the shoulder. Better safe than sorry. I am dropping off a Scout barrel Sat. to have another DI plug put in as the Apex (was) my favorite hunting rifle.
 
I tried eye balling it where the breechplug threads end and where the lands start. Its pretty close. It looks like the powder column should make it to the lands. It is a long breech plug and it only takes 12gr of N110 to completely fill it. I don't have any SR4759. I will look into those borescopes.
 
Didn't see where anyone answered the wad question so a .460 45cal dry wool wad would be what I would try. Again you may very well be OK with the breechplug you have as there isn't very much chamber left in front of your plug, I'd venture to say about 1/4" maybe a touch more. My reasoning for the wad is only to take up space. I never used them or sub bases when I use to shoot sabots. Any kind of endoscope or borescope that will let you have a visual on that area will work. I don't often use mine only when I notice copper fouling. (Sabot-less)
 
Go back three pages on this smokeless section, we have instructions on how to determine the length of your powder column. the thread is called determining the length of a powder column in my CVA Scout, or something like that. long story short, it goes like this. use a dowel or appropriate sized drill bit butt end etc. something that will slide in the breech and through the plug threads but stop at the start of the rifling. I used a shotgun cleaning rod wrapped with wide masking tape, and when it got past the plug threads it was kinda tight and I twisted it in there until it hit the rifling and stopped.
 
once you have your dowel etc. in there all the way to the rifling, put your bullet or saboted bullet in the muzzle and push it down until it stops against the dowel. now while your ramrod is in the barrel, mark it at the muzzle with tape etc. now pull the dowel out of the breech and push your bullet etc out of the barrel and replace your breech plug.
 
now load your gun with your charge and bullet and look at the mark on your ramrod. If it is not quite down to the muzzle you are good to go meaning the base of your bullet is at least as far up as the rifling start. the trickiest part of this operation is getting just the right diameter of dowel or tape wrapped dowel so that it will get barely past the threads but still be able to go a little further and get to the rifling starting point where it gets stopped. what we are calling a powder chamber on these 45-70 conversions is actually what is left of the old 45-70 chamber. on a shorter hankins plug there is about 1/2" of unrifled chamber left there, with your ASG plug it will most likely be much shorter than that. kip
 
with this method I was able to determine that my 45 gr charge of Imr 4227 in the cva scout conversion had my bullet's base at least 1/8" to 3/16" up into the rifling. that was a good thing because it was my most accurate load so far. 250 gr barnes tez and wool wad also.
 

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