Tannel Firing Pin Bushing Cures Primer Cratering
Shooters who convert factory actions to run 6BRs, 6PPCs or other high-pressure cartridges should consider having the firing pin bushed. These modern cartridges like to run at high pressures. When running stout loads, you can get cratering caused by primer flow around the firing pin hole in the bolt face. The reason is a little complicated, but basically the larger the hole, the less hydraulic pressure is required to crater the primer. A limited amount of cratering is normally not a big issue, but you can reduce the problem significantly by having a smith fit a bushing in the firing pin hole. In addition to reduced cratering, bushing the firing pin often produces more consistent ignition.
This is a highly recommended procedure that our editors have had done to their own rifles. Greg Tannel (Gre-Tan Rifles) is an expert at this procedure, and his turnaround time is fast — usually 2-3 days (shop time). Current price for a bushing job, which includes turning the firing pin to .062″, is $82.00 including USPS Priority Mail return shipping.
If you have a factory rifle, a bushed firing pin is the way to go if you are shooting the high-pressure cartridges such as 6PPC, 6BR, 6-6.5×47 and 6.5×47. This is one of the most cost-effective and beneficial upgrades you can do to your factory rifle. For more info on the Firing Pin Bushing process, visit GreTanRifles.com, or email greg [at] gretanrifles.com. (After clicking the link for GreTanRifles.com, Click on “Services” > “Shop Services” > “Bolt Work”, and you’ll see a listing for “Bush Firing Pin Hole & Turn Pin”. Select “View Details”.)
Firing Pin Hole Bushing by Greg Tannel
Work Done: Bush firing pin hole and turn pin.
Functions: Fixes your cratering and piercing problems.
Price: $75.00 + $7.00 return shipping
Total Price: $82.00Actions for which Bushing is Offered: Remington, Winchester, Savage, Sako, Kimber, Cooper, Nesika, Stiller, Bat, Kelbly, Lawton, Surgeon, Borden, Wichita, Hall, CZ, Ruger, Mauser, Howa, Weatherby, Dakota, Pacific Tool, Phoenix, RPA Quadlite, and Defiant bolt action rifle or pistol. Note: There may be extra tooling charges for case-hardened style bolts (Mauser, CZ, and similar) .
Actions for which Bushing is NOT Available: ARs, Accuracy International, Desert Tactical Arms, Big Horn, Rim fires, Falling block, Break open, Lever, Pump rifles.
How to send your bolt in to be bushed:
You can send your bolt snail mail, priority mail, UPS, Fed-Ex. What ever you prefer. Please include your name, phone number, and return shipping address. Turn around is normally 1 to 3 days shop time (plus shipping time). We usually do them the day that we get them in. Total cost is $82.00 for one bolt or $157.00 for two (this includes return shipping, priority mail.) Three or more will be sent back to you UPS and we will have to calculate extra shipping. We can overnight them at your expense. Check, money order, or credit card is fine with us.
Similar Posts:
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- Primer Crater Cure — Firing Pin Hole Bushing by Greg Tannel
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Tags: Bushing, Crater, Firing Pin, Primer
I had a remington 700p in .223 that I converted to a 6br. after I opened up the bolt face the firing pin hole was a little loose. I was having issues with primers actually getting cut around the firing pin hole and jamming the firing pin during a match. I sent the bolt out to greg and he fixed it right up. ceramic coated the bolt too. highly recommended.
I have read a lot about bushing the firing pin. While I am not saying “don’t do it” if we do do this, are we not just hiding the pressure signs? Think about it — we use primer cratering to know if a load is getting too hot for the gun, then we bush the firing pin and now we can run hotter loads? To me that is like saying the car has a rattle above 70 MPH, so if you are driving 75 turn up the radio so you can’t hear the rattle.
Using primer cratering as a pressure indicator is not recomended because of the great variation of primer metal hardness.
A better way is to measure the diameter of the head of the case before and after firing. Use a good micrometer for this. If the expansion after firing is over .001″ the load is too hot for that combination.
Be aware that different lots and makes of brass have different characteristics and may react differently to pressures.
Mixing different makes of brass is not a good idea.
Weigh your brass and try to keep it in lots of +/- 5 grains.
I had Greg bush my firing pin hole as well as removing and filling in the ejector hole in the bolt face of my new Dasher build.
The fired primers and caseheads come out looking perfect, but………..short of using Quickload is there any other pressure indicator left to me besides loosened primer pockets?
Regardless, if you’re going to run hot-ish loads and want to keep your brass from being torn up, Gre-Tan is the choice.
A top shelf gunsmith that lives in a town named “Rifle”…..it simply does not get any better!!
Roy
Some of you are missing the point. The BR and 6.5×47 series of cartridges use a small rifle primer. The firing pins in most of the bolts listed have a large diameter firing pin. That is what causes the issues. I have done this on a BAT three lug action that should have been able to take all kinds of pressure but would in fact pierce primers with a warmer 6BR load. Once Greg turned the pin and bushed it, this problem disappeared. This modification is a must have for any one converting to these calibers.
Is this a good idea for cases like the .308 or 7-08? I have a .473 RPSA that I was going to build a 338 Federal with for deer/hog hunting. This article has me thinking about a 6.5×47 instead, but it’s hard to make up for that much bullet diameter even though dead is dead. It’s the blood trail that bothers me, and .338 > .264.
Seems to me that bushing the firing pin is just a modification to hide high pressure signs…
EDITOR: Not necessarily. With Accuracy Internationals for example (the actual AI action) there is a huge gap around the firing pin. This will allow cratering even at very moderate pressures well under the rated case max. I’ve seen that first-hand. Savages also have excess space around the firing pin. This can allow cratering with moderate loads. Again, I’ve seen it first-hand.
That said, if your gun does NOT crater at “practical max” loads, and then you keep going up cratering can, indeed be a sign of high pressure (along with flattening of primer, ejector mark, casehead expansion etc.). It’s smart to do so research on your loads and compare them to what other guys are shooting. Each gun/barrel is definitely different, but if you’re running a “book” load in the mid-pressure range yet getting cratering, it makes sense to bush the pin. You may be quite surprised at how effective this procedure is…