Failure of powder to ignite?

[telshe49]

Today something that has never happened to me before so lm hoping someone here can help.
I was on S/Siberia this morning with my Sharps in 45/70 loaded with 36.3 grains of 4198 and a 326gr FNL bullet. That l loaded up 2days ago. On my 7th shot it appear that l either had a duff primer or no powder in the case. As it happens l had both, the bullet had left the case and engraved the rifling and on removing the case the powder was compressed and slightly blackened but had not ignited. Any ideas of what happened. One for Dromia l think
Regards Telshe49

[meles meles]

The primer could push the bullet forward and into the rifling. Maybe you have that inert, fireproof, powder?



Echoes in here, doesn't it?

[Sim G]

How do you clean your cases? Liquid involved? If so, perhaps a wet case....

[dodgyrog]

If it is a ball powder it will need a magnum primer to fire it up. I had the same problem with Accurate 2520 in a Swede 6,5 x 55

[Sim G]

Never had a problem igniting any ball powder I use, H335, H380 or BL-C(2) using standard rifle primers...

Either way, 4198 is an extruded power...

[dromia]

From the limited information I suspect that the problem arose from a combination of poor boolit retention combined with a light, for the calibre and too hard a boolit.

Basically powders need to be contained as they perform when under pressure, although 4198 is a relatively fast rifle powder it is still a stick powder that needs the right conditions to get it going. A loose fitting boolit can be easily driven forward by the primer flash especially a light one like this, heavier boolits take longer to get moving more mass to shift, this increases the volume that the powder has to combust in and can cause the powder to fail to ignite properly.

What was the hardness of the boolit? If it was a commercial cast then it was likely to be hard cast which doesn't help performance, far higher pressure needed for obturation.

What was the boolit retention? What was the difference between the case mouth inside diameter and the boolit diameter?

What was the cartridge overall length and the boolit seating depth?

What was the distance from the seated boolit to where it engaged the lands of the rifling?

Was it Hodgdon or IMR 4198?

What was the powder case fill, depending in the powder manufacturer it could be around 3/4s of the case capacity?

What was the weight of the powder left in the case after firing?

[FredB]

Nobody has mentioned ambient temperature. When I first started shooting .300 Sherwood, I used 10grn of reloader 7. This load proved to be accurate and reliable until one freezing morning I turned up at the range and found that the ammo would not go off. My vehicle is a Hilux pickup truck with a hard top, the ammo was in the un-heated back.
I experimented with warm and cold ammo and confirmed that the problem was temperature related.
Fred

[telshe49]

Good morning
Thank you for your replies. Firstly Simon, the cases were dry l have never put them in water. Dromia the bullet is cast. With about one tenth Linotype and the rest is lead, they are sized/lubed and gas checked. The bullet is crimped. The inside case dia is .456. Col is 2.522 inches. Bullet seating depth according to Quickload is 0.455 inches the was sized at .457 .The distance where the bullet engraved the lands is unknown. The powder was IMR 4198. Powder fill was 79.1. The remaining powder looked the same weight that was loaded though it was a compressed lump that fell apart when touched. There was a lot of burnt residue up the barrel between shots and also a lot of smoke coming from the breech when reloading the next round. FredB. The temperature was about 40/45f a nice sunny day . All my ammo is kept in a Peli case in my car on the way down to Bisley. I have had this Sharps since 1992 it was bought from Sandy McNab. Slightly off topic l was with the Classic and Historic and somebody had heard that the 100yd firing point was being extended across S/S and the 200yd firing point was being scrapped any body any thought on this. Any way many thanks for your input my little problem.
Regards Telshe49

[dromia]

One thou boolit retention isn't much I usually go for at least double that.

Assuming that the powder and the primers are fine then I would try and get a bit more grip on the bullet in the case and see if that makes a difference.