Help, I cant get my 375 BIg bore to shoot.

[andym79]

Hi guys got a 375 big bore a few months back. Shot it a little with some Trailboss at 50 and it did nicely.

More recently I tried it with the same load at 100 and it did poorly.

I figured, it just needed a little more fire in the hole (I have tried this once before with VV N110, I had some success in terms of accuracy, but came across an issue that made me discontinue the load
http://castboolits.gunloads.com/showthread.php?249088-Vihtavuori-N110-in-30-30-or-375W-38-55

http://castboolits.gunloads.com/showthread.php?250420-Causes-of-hard-bolt-lift

Though I am not entirely convinced that is wasn't a combination of an uncleaned rifle and an issue with the case). So I tried Lyman recommended loads 2400 21 grains, H4227 23 grains and H4198 25 grains. The all struggled to hold minute of dinner plate. So I figure plain based bullet, they need to be pushed softer.

So I tried some gentle loads, 18 grains of H4198, H4895 24 grains and H4227 15 grains. All nice to shoot but they too held minute of dinner plate.

I even tried a load that both QuickLoad and a couple of guys I know at the range have had luck with, in theory from them and the programme it should be sweet 18.5 grains og 4227, but no luck.

The bullet is cast from Lee 379-250RF, the alloy is PB 4:1 Lino. The bore slugged at .376, I size the bullets to .377, I use a 50:50 lube on them.

I want to shoot my big bore at speeds above 1000 fps and further out than 50 yards. I have never had such trouble getting a rifle to shoot cast. Even the 6.5x55 was a picnic at 1300-1600 fps compared to this and I though the bigger the bore the easier cast tended to be?

The twist in this rifle by the way is 1:12 so it should be able to stabilise this bullet at a very low speed.
I shouldn't need a harder alloy at this speed nor should I really need a GC to get 3-4MOA at 100 yards at 1000-1500 fps.

I even tried loads with and without a filler for my real light loads and it made no real difference. Any ideas as to why this rifle should be so much harder to get shooting cast than the rest of mine?

[Tatume]

Hi Andy,

My recommendation is to thoroughly clean the barrel and then shoot some jacketed bullets with a known good load. I suggest the Sierra 200 grain bullet and the minimum load of H4198 from the Hodgdon web site:

http://www.hodgdonreloading.com/

Don't use less than the recommended minimum. If ammo so loaded shoots well, then you've narrowed your search to the cast bullet ammo. If not, then there may be a problem with the gun.

Take care, Tom

[Dan Cash]

For the power level you are seeking, I suggest that you sell the .375 and get a .357 which more favors your indicated performance level.

[crash87]

I'm going to throw this out there, as I have a bigbore, a no.3 and a Marlin 375, and all are different. The bigbore being the most "indifferent"
1st off my bore slugs .376 also but my chamber is huge and long. My 1st attempts with cast were dismal at best. It shot jacketed fine but cast, it did what yours did, minute of trash can lid.
If, it shoots jacketed with acceptable accuracy, try it and see, and doesnt shoot cast, as you have found. Make a throat slug and measure, to see what you have, you may be quite surprised.
Again, IF, this is the case, Get a mold to fit the throat of your rifle, don't worry about the bore dia. This may mean, going the custom route, such as LBT, or Accurate, to get what you just may need, a dedicated bullet for your gun.
FYIW, I "can" (but dont) chamber and shoot 38/55 brass out of mine, i.e. long chamber, and I fill the throat of my rifle with .379 sized bullet. Yes it took awhile to figure this out, and it came with a lot of help from Veral Smith.
CRASH87

[andym79]

1st off my bore slugs .376 also but my chamber is huge and long. My 1st attempts with cast were dismal at best. It shot jacketed fine but cast, it did what yours did, minute of trash can lid.
If, it shoots jacketed with acceptable accuracy, try it and see, and doesnt shoot cast, as you have found. Make a throat slug and measure, to see what you have, you may be quite surprised.
Again, IF, this is the case, Get a mold to fit the throat of your rifle, don't worry about the bore dia. This may mean, going the custom route, such as LBT, or Accurate, to get what you just may need, a dedicated bullet for your gun.


I could try shooting them as they drop .380", I also have the Lyman 375449, which I haven't tried yet. I may try these two things before I buy any jacketed bullets.


For the power level you are seeking, I suggest that you sell the .375 and get a .357 which more favors your indicated performance level.

You misunderstand, I would actually like to get 1600fps+ out of them, but I cant even get 1300fps right now. Also the 357 doesn't let me shoot 250 and 280 grain slugs and would be poor for pig hunting.

[TXGunNut]

Try the 375449, load development for it in my BB was like the Cowboys at playoff time; one and done! Was almost disappointing but I sighted in a new receiver sight and shot ten rounds better with that initial load than I normally shoot with irons. My recipe is 32gr Rx7, 2.560 COAL.

[andym79]

Try the 375449, load development for it in my BB was like the Cowboys at playoff time; one and done! Was almost disappointing but I sighted in a new receiver sight and shot ten rounds better with that initial load than I normally shoot with irons. My recipe is 32gr Rx7, 2.560 COAL.

Thanks for that I will give it a go. Can't get Rx7 here unfortunately, a shame as I keep hearing good things about it. I will try loads I have for it either side of Rx7 H4198 and H322.

I think the chamber length might well be a major factor in why this rifle is proving inaccurate. I haven't chamber casted it yet, I did however check this morning how far out I could seat the 375449 before it touched the rifling (in a couple of my other rifle I have done this and find it increases accuracy, in those 50th will do it) not in this rifle, to kiss the rifling I had to seat the 375449 out to an OAL of 2.775" a full 215th past suggested OAL, which is what I usually start with. Fingers crossed the 375449 does the trick if not its 571 or 378-312 or a custom projectile with a different profile.

I don't think I could get a way with seating the 375449 that far out it would only be seated to .320 and seating a bullet by less than its diameter is far from ideal (pistol cases excluded). Even if it worked it would render by 94 a single shot!

[Doc Highwall]

A fatter/larger diameter bullet will touch the rifling sooner making the OAL shorter. Can you chamber a larger diameter bullet and what diameter are your bullets dropping from your mould? You said you size them .377" which is only .001" larger then your slugged diameter, I would recommend sizing at least .002" larger then your slugged diameter and better yet even larger.

[TXGunNut]

Thanks for that I will give it a go. Can't get Rx7 here unfortunately, a shame as I keep hearing good things about it. I will try loads I have for it either side of Rx7 H4198 and H322. -Andym79

Rx7 has been a bit spotty around here as well, I think you're on the right track with H322 but I can never find much Hodgdon powder around here, haven't found any H322 when I looked for it. Haven't heard much about H4198 and haven't tried it either. Rx7 seems especially well suited to the 375 Winchester and the 35 Remington among others but I read similar reports on H322.
COAL (and powder charge) came from Lyman's CB Handbook, made sense looking at the crimp and lube groove configuration. I don't lube the top two grooves, used the RCBS 50/50 storebought lube and a Hornady GC.

[44man]

Never shot one but 1 in 12" might need a lot faster with a harder boolit. Try creeping into jacketed territory. I feel water drop WW boolits and get the velocity up. Spin stability seems to be the problem. Good at 50 but poor at 100 indicates that.

[264 Win Mag]

Though I am not entirely convinced that is wasn't a combination of an uncleaned rifle and an issue with the case). So I tried Lyman recommended loads 2400 21 grains, H4227 23 grains and H4198 25 grains. The all struggled to hold minute of dinner plate. So I figure plain based bullet, they need to be pushed softer.

I just tested the 235 gr Ranch Dog with your H4227 load and man it was the worst test group I have ever fired! First two shots keyholed badly and were at least a foot apart on the target and I never could figure out where the third round went. Will be bumping it up to 27 grs. and re-shooting. I am with those above that this rifle needs to be pushed harder to stabilize and the bullet you are shooting is bigger than the one I am using so probably an even bigger factor for you.
Good luck,

Thomas

[fouronesix]

andym79,

You may have dismissed something obvious at the very beginning. Try a similar bullet that is gas checked, sized to 376 or 377. Doesn't have be be really hard, maybe BHN 12. Re-try those similar mid-pressure, mid-velocity mid-burn powder loads with the gas checked bullet.

[JohnH]

I once had a 375 JDJ barrel for my Encore that wouldn't shoot cast worth a tinkers dam. What made the situation so frustrating was that in the months previous I had been shooting an NEF 38-55 that it seemed there was no wrong I could do. 9 grains of Blue Dot and the Lee 375-250 you mention gave 1250 fps and great accuracy all day. The Lyman 375449 also shot very well and with that boolit and a full case of 1680, (1750 fps) I killed two deer. Nice. But the 375 JDJ just wouldn't shoot. I believe to this day the problem was the 1-12 twist of the Encore barrel, as the NEF was a 1-18 twist. I've read of people swearing by the 375 Winchester and cast, but I always had my doubts.


I read through the posts rather quickly, all I can suggest is slug the barrel and make a chamber cast and be sure you are matching the boolit as closely as possible to the gun. I did all my sizing in a .379 die, if you are dropping a boolit of 377-379, try some liquid alox or 45-45-10 on a handful of unsized boolits and see if that helps.

[andym79]

Thanks for the input guys. A harder alloy couldn't hurt, gas checks will certainly help. I don't think stability is the issue, the 1:12 twist according to my calculation could stabilise a 300 grainer at 1300fps. So a 250 at 1500fps shouldn't be a problem. I will try some more loads and the larger bullet.

[Frank46]

When member here Buckshot ramrodded a .375 cast bullet deal with lee for one of their 6 cavity molds there was some discussion regarding what the mold should drop the bullets at. Going from memory here but the general concensus was at or near .380 to allow the members here to size down to what the diameter they need and to have that flexibility with the fatter bullet. That plus there was a thread on verals gunboards section about the rather big throat commonly found on these rifles. Seems he sent veral either a pound slug of the throat or diagram of the throat. And veral cut a bullet mold taking in the fat dimensions of the throat. From what little I remember the shooter reported excellent accuracy where before he had none. I think the shooter is a member here and if he see's this may be able to contribute some info. But I cannot remember his name. Frank

[sthwestvictoria]

I would agree with 44man that an easy variable to remove is hardness - use some straight lino or Wheel Weights and/or oven heat treat and quench, leave for a week to harden. This removes that from the equation - what the engineers call the single points of failure.

That mould is a non-GC by the look of it however will you trial crimping some on and sizing them?

[andym79]

I would agree with 44man that an easy variable to remove is hardness - use some straight lino or Wheel Weights and/or oven heat treat and quench, leave for a week to harden. This removes that from the equation - what the engineers call the single points of failure.

That mould is a non-GC by the look of it however will you trial crimping some on and sizing them?

As I stated in an above post I also have Lyman 375449 which is a gas checked mould. I am taking 50 of those out to day to see how they perform. If they too fail I have 5kg of lino so I could cast up 50 and see what happens.

I not sure why the lead would need to be real hard though I have pushed BHN 12-14 mixes with a GC to close to 2K in other rifles.

[sthwestvictoria]

I see the benefit not being that you really need alloy that hard , rather you have removed that single point of failure from the many cast bullet variables.

A few people have found the 35 Whelen seems to do better with harder bullets.
The top target is one of best so far with oven heat treated WW, 2% tin.
125706

Then top target is the same in every way except air cooled WW 2% tin, the lower target is then 50:50 Pb (roof flashing) to WW with 2% tin:

125705

Top target was with my M70, the lower one with the 35 whelen in mauser 98:
125712
Left to right 50:50, straight WW and then heat treated.

[andym79]

Hi guys took out the big bore yesterday. With 50 rounds, 16 x 3 loads and two fouling shots to clean out the oil etc.
Well results were mixed, 250 grainn lee mould.

Trailboss 9.5 grains 3 1/4"
AR2205 (H4227) 14 grains 3"
AR2219 (H322) 23 grains 4 1/2"
AR2206H (H4895) 25 grains 8 3/8"

With the Lyman 375449 GC (which I find actually drops at 280 grains)

AR2205 (H4227) 20 grains 1 3/8"
AR2207 (H4198) 24 grains 2 3/8"
AR2219 (H322) 27 grains 1 3/16"
AR2206H (H4895) 29 grains 2 7/16"

Other loads are not worth discussion. Pushing the bullets over 1600 resulted in terrible accuracy, which surprised me given that they are gas checked.

Conclusions:

1) The big bore likes H322 and H4227.
2) The Lee design would probably do better with a harder alloy, it wasn't driven hard by any of those loads.
3) A custom mould would improve matter further.

Best two groups shown below H322 and H4227.

[Doc Highwall]

andym79, what distance are you shooting at and what kind of sights are you using?

[andym79]

This target was placed at 100 yards, using peep sights. I might add that the only difference between dinner plate accuracy and 8 or better MOA, that all I changed was seating the bullet deeper, to suggested depth rather than reducing the jump. Usually I find seating out helps, but the rifling is so far out on this rifle that I suspected all that I did was reduce neck tension and cause inconsistent pressure and burn on launch, after all the jump was still likely 75th. The best that can be done with this rifle, I believe, without a larger or custom bullet has been achieved in those two groups above.

A chamber cast needs to be done to confirm my suspicions. Why would Winchester have made a chamber for 335 grain bullet when you couldn't cycle them through a 94 action? It might make sense on a single shot rifle!

[TXGunNut]

Looks like you're onto something with the H322 and H4227, just wish you could get another 2-300fps. I neglected to record casting notes on my 375449 boolits but I'm relatively sure I didn't heat treat them. I wouldn't be surprised if they are straight WW's but they may be 50/50 WW/PB.

[sthwestvictoria]

You are certainly putting in the hard yards trying to get the rifle to shoot!
I would be fairly happy with some of those smaller groups at 100yards.

Apparently, unlike 30-30 1894 actions there can be significant freebore in the 375, this is one image from some quick googlefu:
http://i56.photobucket.com/albums/g181/ReeceTalley/freeboreIV.jpg
From this thread:
http://castboolits.gunloads.com/showthread.php?34071-Cast-bullets-for-375-Winchester