Sharps might have a headspace problem, it's odd.

[guninhand]

Hi folks. Recently got my Farmingdale Sharps, now in 45-90, back from barrel maker and had a chance to shoot it yesterday. Load was 83gr Olyde Ennisford 1 1/2 with a .06LDPE wad, 540gr Postell boolit, Win LRP and newspaper wad between flash hole and powder column. Every round fired had primer brass flow into the firing pin hole in the breech block. The primer brass then got smeared out as I dropped the block to extract the round.

Uploaded at Snapagogo.com

To check headspace, I put feeler gages between the block face and barrel, both with and without a brass chambered and with and without the lever captured with the povot pin. In all cases the largest feeler was .004 inch, and according to what I could find on the internet, up to 0.007 inch should be acceptable for this gap. The base of a seated brass appears perfectly flush with the end of the chamber

URL=http://www.snapagogo.com/photo.php?id=84343][/URL]Uploaded at Snapagogo.com

If it isn't headspace, then the only other thing I can think of is the shock wave from the primer partially bouncing off the powder column and forcing the primer into the firing pin hole. I did a double compression on the powder, drop tubing 56 grains and compressing, then drop tubing 27 grains and compressing that. The column gets fairly solid that way. Any thoughts?

[Skipper]

Hi folks. Recently got my Farmingdale Sharps, now in 45-90, back from barrel maker and had a chance to shoot it yesterday. Load was 83gr Olyde Ennisford 1 1/2 with a .06LDPE wad, 540gr Postell boolit, Win LRP and newspaper wad between flash hole and powder column. Every round fired had primer brass flow into the firing pin hole in the breech block. The primer brass then got smeared out as I dropped the block to extract.

If it isn't headspace, then the only other thing I can think of is the shock wave from the primer partially bouncing off the powder column and forcing the primer into the firing pin hole. I did a double compression on the powder, drop tubing 56 grains and compressing, then drop tubing 27 grains and compressing that. The column gets fairly solid that way. Any thoughts?

There is no shockwave as this is a deflagration, not a detonation. You may have to bush the firing pin hole.

[guninhand]

I was thinking of the shock wave originating from the primer alone, partially "bouncing" off the base of the powder column before the black powder got going.

[bigbore52]

Guninhand.

For the primer brass to move back like that does limit the possibilities and you'd think it should be a simple matter of working through it step by step. But it may not be so - let me explain how I went about similar problem as yours with some suggestions for you to try.

As I don't know your situation, please excuse me if my suggestions are not withing your competence

A chamber cast with a raised wall around the bore to get the rim in the cast is a start - it's fiddly but achievable and I'd stress you need to build a wall up so the cast actually fills the rim...otherwise your cast will just be the chamber itself..that will give you a pretty good look at how it was cut and allow you to take some measurements- it will also identify any high spots or anomalies in the recess that may cause problems with chambering such as burrs or dags from cutting (it does happen unfortunately)...but please bear in mind - there are a lot of other factors to check but the cast is important to sort it out.

I use Starline in my 45/70's and haven't had any primer issues - found the cases required very little uniforming first up. Am assuming their 45/90 is made similarly? Other case brands I use do require some work to make them uniform....I do this prior to annealing and before first use - primer socket standardisation with one of the commercial tools is recommended along with uniforming the flash holes. Some manufacturers' quality control leave a lot to be desired so worth checking - I shoot the 45/70 as well as the 45/120 and have done this for all my rifles.

Agreed that the space can be up to 7thou as they state but equally the rim thickness on cases does vary considerably and is also worth checking - to do that get yourself a flat plate and some verniers with the slide that allows for depth measurement - it is too difficult and prone to errors just putting the rim between the jaws and measuring that way as some rims are bevelled slightly or tapered so you can't get accuracy just measuring the rim thickness between jaws ...what you do is stand your case base down on the plate so the base sits flat and measure its total overall length from the top of the case to the base plate with the slide on the verniers...after that measurement zero your vernier (if it's digital) and then repeat that measurement from the top of the case to the inside of the rim by sitting the slide on it - (if you don't have a digital one then record the measurements and subtract the second from the first measurement) what you then have is your rim thickness.

Do all your cases and record each measurement - you'll then see how much tolerance the manufacturer allowed in his case production run....you'll be surprised at what you thought.

To check you rifle and get an exact rim recess measurement (aside from the chamber cast) I use this method - If you had a lathe, or know someone who does you can easily make a brass dummy with a thicker rim; it doesn't need to be the shape of the case but just long enough to chamber and have a rim on it - that's all you need - what you do is make the rim over thick say 15 thou which you know won't allow the breech to close and then progressively remove thickness from the rim until it actually chambers without too much force..seeing the 45/90 case head spaces from the rim, this method will give you a more accurate measurement than a chamber cast...what you end up with is a dummy head spaced exactly for your rifle...stamp it or scribe on it what the measurement is for reference as you can use it on most of the 45 rifle family to check but importantly it comes in very handy when trying to convince a gunsmith that he cut the rim too deep ..ut use it along with the cast in sorting out your problem as they both compliment each other.

It may be a matter of working through each variable before identifying the exact problem...as I mentioned, it may not be a single factor but a combination ...generally they are pretty good, but some of these rifles can be quite fastidious as to what you stuff in them and the results you get will vary each time but it's important to only change one variable at a time as you are working through it.....if you know there's nothing wrong with the rifle and case specs than that only leaves the load as the cause....

I'd also consider changing primers...try various brands with the same load. My Sharps 45/120 likes magnum primers over LRP and of those, prefers Win over Fed and others - again check these as I did and you'll also find that not all primers are built to the same specs in dimensions - I did have some problems with primers moving with some brands.....there definitely is a variation between brands

Anyway, just a few thoughts and comments as to how you can go about it - hope it helps...........and good shooting.......Lee

[guninhand]

Lee, thank you for all those suggestions and the effort to post them. I was hoping this would be a more common problem with a ready solution. My brass was all new unfired Starline that had been annealed. The smith had mistakenly chambered the barrel to 45-70 then rechambered it to 45-90 as per my order. That's the only quirk I know of. All hit primers looked identical to each other and all case bases looked precisely flush with the chamber mouth. Using a mechanics automotive mirror the rim recess looks exceedingly well done. I have the cerrosafe, dam putty and calipers to do measurements. I uniformed the case flash holes but didn't bother with a pocket uniformer. Primers were seated with a Forster priming tool which gave a good, consistent feel and primers seated tight and uniform. John

[Gunlaker]

I would remove the breech block and inspect the firing pin hole. Skipper may be correct.

Chris.

[Boolit_Head]

I am having a little trouble understanding what I am seeing in the picture of the primer. Around the firing pin strike strike the next circle is that indented or standing proud of the rest of the primer? It sort of looks indented to me like there is a bushing around the firing pin that is raised from the breech face.

[Nobade]

Breech block is damaged around the firing pin hole. It needs to be flat and smooth, and the pin needs to have very minimal clearance in the hole. No headspace problem.

-Nobade

[guninhand]

I am having a little trouble understanding what I am seeing in the picture of the primer. Around the firing pin strike strike the next circle is that indented or standing proud of the rest of the primer? It sort of looks indented to me like there is a bushing around the firing pin that is raised from the breech face.

Upon firing, the primer is pushed back against the breech face, then expands into the firing pin hole. As the block is lowered, the brass in the firing pin hole is now an obstruction to movement, gets smeared and you can feel it being cut. At the time I was doing a test comparing large rifle primer to large pistol primer. Projectile speed was 1320 fps, I fired a total of 8 rounds. When I fired a case with a pistol primer, Federal brand, it actually cut a hole in the primer and I stopped shooting.

[guninhand]

Breech block is damaged around the firing pin hole. It needs to be flat and smooth, and the pin needs to have very minimal clearance in the hole. No headspace problem.

-Nobade

Fortunately the breech block is undamaged and all smooth, flat and factory original. I know the original owner, who fired less than 150 rounds when it had the factory 45-110 barrel, I fired a few 45-110s out of it myself and it didn't have this problem. I had to pick small pieces of brass out from around the firing pin when I inspected it.

[BrentD]

This happens to me all the time. It's actually pretty normal for Sharps rifles. You do have to periodically clean your firing pin channel to get the shavings out of there. No big deal. The primer is simply being set back by the powder charge. It flows into the pin channel which, because it is on an descending angle, creates a guillotine-like cutter that shaves off the back of the primer when you lower the block.

You can effectively eliminate this problem by recocking the hammer and firing again. The second blow will drive the pin back into the case. Without a powder charge to set it back, it will now be too far forward to be shaved by the block when you open the action. This is somewhat of a pain in the butt, but it will solve your problem.

[martinibelgian]

I was thinking of the shock wave originating from the primer alone, partially "bouncing" off the base of the powder column before the black powder got going.

I'll go with chris and Kipper - the firing pin hole needs to be bushed - if the primer can flow back in the hole with the firing pin in place, then there's too much space between the 2. Solution? Bush the firing pin hole. Problem solved.

[Lead pot]

Here is my thought with your problem and I will use some photos to make it a little easier to follow what I'm saying.
First I think the firing pin might have been replaced in the farmer with one that is undersized diameter at one point giving the primer room to get pushed back against the breach block and flowing into the pin channel.

You said your double compressing your powder. What this is doing is, your making a solid slug of powder and doubling the compression your making your powder the whole charge like the front portion of the compressed powder in the photo. This powder is compressed .400". Now you have a solid block that is dense not letting the pressure from the primer to dissipate like it would in a loose or uncompressed powder charge. This is amplified with the paper disk you mentioned over the flash hole and this puts more pressure against the primer forcing it back against the breach block before the main charge goes off.

I used to use heavy compression of .400" when I was using the Goex Express powder because it performed best with heavy compression and I also used a paper disk under the powder over the flash hole and at times when I used a pistol primer under the primer so the pistol primer that is not as deep as a rifle primer so it was flush with the case head so the firing pin did not damage the pin channel in the block. What happen was what you see on the face of the breach block in the photo below. Those marks around the pin hole are gas cuts caused by the primer gas blow back that was restricted by the heavy powder compression and also the paper over the flash hole forcing more pressure from the primer back and past the primer. In my case the firing pin channel is tight with the firing pin and forced the gas past the primer cup gas cutting the cup and primer pocket and then damaging the breach block face.
In your case it's forcing the primer cup into the pin channel.

A head space problem like the rim recess cut to deep you will see maybe the primer cup get pushed back some but also stretched cases or cases pulled apart.

[guninhand]

Before I read BrentD's post, (and the ones following) I decided to test my theory of primer set back due the cement like texture of black powder column from doing a double compression, i.e. the shock wave hits what's like a solid wall, instead of the more loosey goosey kernels when compression is not so close to the brass base. I loaded up 3 rounds with first, 64 grains no compression, no drop tube; 2nd 73 grains drop tube and 0.218 inch compression, third 83 grains, 0.565 compression,( one only from the top) and drop tube. Rushed to range, shot 'em and came back. The results are shown below, the 64 grain on left, 73 grain middle and 83 grain right. more pressure equals more smear. Unlike the first rounds yesterday, these rounds were previously fired cases and I loaded with almost no neck tension. All case extracted smoothly any primer brass being shaved off. BrentD's exlpaination looks like the answer to me. What a relief.

Uploaded at Snapagogo.com

[montana_charlie]

How far does your firing pin protrude from the face of the breechblock?

[Exal]

I don't know if this has been said yet, but I find the same thing on my 45-70 sharps. I've kind of come to the conclusion that it might be from making the primer pockets the same depth. This in turn makes the primer pocket to deep for the primer and you get a little set back when the powder goes off. Do you use Lyman's primer poket uniformer On your cases?

[Skipper]

You might want to check with Shiloh to see what they have to say.

https://www.shilohrifle.com/shop/hel...b96668759868f3

tel:406-932-4266

[Gunlaker]

It wouldn't hurt to try calling Shiloh. I have never had any of my Shiloh's or C. Sharps rifles with fired primers that looked anything like that. The only thing close is a Winchester 1885 target rifle with the original large diameter firing pin. When I tried pistol primers in that rifle they looked like a less severe version of what you posted. Rifle primers look normal though.

Chris.

[1Hawkeye]

Guninhand, The older Farmingdale rifles copied the larger firing pin hole of the original Sharps. What your experiencing is primer flow back . When the new owners took over in Montana they changed this dimension and they can fix it for you. I remember reading as a kid that Elmer Keith had this problem on originals and the Farmingdale Sharps he tested for guns & ammo magazine when Shiloh first came out. The old timers trick was if you couldn't drop the breach block then you recocked and drop the hammer again and this will flatten the primer so you can open the block.

[EDG]

The firing pin diameter looks ok but the firing pin hole is waaaaaaaaaaaaayyyyy too big. It looks like cheap break open shotgun firing pin hole.
The existing block could be bushed or just replace it, though replacement would not be cheap. My Pedersoli Sharps firing pin holes are about 1/4 the size of yours.