Single Shot Light Primer Strikes

Share your experience in caring for your favorite Rossi with other members or ask the question that you cannot find the answer to!
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Single Shot Light Primer Strikes

Post by Ranch Dog »

It seems that the Rossi Single Shot's are known for light primer strikes but there is not a lot of definate information about curing the issue so I wanted to add a list of steps that should be considered in curing the issue if you experience problems.

Correcting Single Shot Light Primer Strikes:
  1. Remove the Rossi Hammer Extension1
  2. Check and adjust the firing pin protrusion at the breech face2
  3. Adjust Hammer Spring3
1The easiest to check the issue is to insure that the problem is not caused by the Rossi hammer extension. I was able to find one text from back around 2005 where a gunsmith that worked with these rifles felt that the weight and mass of the Rossi supplied extension was too heavy for the design. He cited that in every case that he had worked with, it eliminated the issue. He went on to say that over time (wear in) that the extension could be added back to the rifle. Others claim the opposite but this specific step curred the issue with my R762. As easy as it is to remove the extension, this should be the first step.

2Make sure that the hammer nose is allowing the full extension of the firing pin. The length that the firing pin should be exposed outside the breech face is approximately .042". This work is detailed in Light Hammer Strikes.

3f100cleveland told me via PM that he had to bend his hammer spring to solve his issue on the R762 but I did not need to go this far. Hopefully he will add his comments to this post.[hr][/hr]
The problem I had existed with reloaded ammunition only using CCI primers. I wasn't about to stop reloading or switch primers, in that I keep about 40K on hand, I would sell the rifle first. I started with step two, which I'm happy I did as the firing pin protrusion was poor, but I still would try step 1 first. The work on step two brought be to about 95% reliability with the CCI primers and removing the extension has brought the dependability to 100%. I have shot the ammo with Federal, PPU, Remington, Winchester, and Wolf factory ammo. I have reloaded Federal, Fiocchi, PMC, PPU, and Winchester brass with CCI primers and they have been proofed at 100%. I toss Remington brass as it uses small rifle primers. The same for S&B brass but it has a undersized large primer pockets and have damage every case trying to correct them with an appropriate tool.
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Re: Single Shot Light Primer Strikes

Post by Tuco Ramirez »

I have read not all primer cups require the same amount of pressure to fire. I will assume CCI uses a harder material? When available I have preferred CCI through the years. Anymore I am happy to get whatever I can, even considered using Wolf.
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Re: Single Shot Light Primer Strikes

Post by Archer »

It used to be that CCI 'military' and Winchester primers both were known to use harder cup material and potentially be hotter than standard primers from other manufactures.
Current production Winchester primers may or may not be the stiffer material.

Federal primers by contrast are generally thought to be softer than other manufacturers particularly their Match or Bench Rest versions. There are a lot of cautions against using Federal primers for reloading rounds intended for use in semiauto weapons with floating firing pins. Specifically these cautions apply to the M1 Garand and the M1A/M14 style rifles and to a lesser extent to the AR and possibly M1 Carbine style rifles. The major reason is that the floating firing pins continue to travel after the bolt stops until contact with the primer stops them. This can be a particular problem with the M1A /M1 Garand rifles IF the receiver bridge is out of spec and allows this contact before the breach is fully closed and an out of battery discharge results.

Running counter to that argument are the large number of folks who use the thousands of rounds they've loaded with Federal match primers and shot through M1As and M1 Garands that haven't detonated prematurely as evidence it can't happen.
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