Gunsmithing Q&A with Ken Brooks

kenBrooksOne of the best benefits of being a Silver Member of the Gun Club of America, is the “Ask The Pros” forum on the GCA website. Ken Brooks, AGI Instructor and owner of Pisco Gunsmithing visits there everyday to help gunsmiths with particular problems they are experiencing. Here are his answers to some recent questions that may help you as well.

One day you may be stuck with a similar problem as these guys, so listen well, Grasshopper.


I have a Remington 700 BDL that I acquired some years ago as a project. The stock was broken so one day at a gun show I picked up a nice used stock. Fit was perfect as if it was original. The gun does show outside wear but how do I determine if the barrel is shot out. I ask because when at the range the first shot is dead on bulls eye, second a inch out, and the third goes about 6 inches out. Now some of you will tell me its shot because its a 264 magnum, but all barrels have a life–just 264 is usually shorter then most. Some have said to glass bed it? Just wondering the opinions of the pros. How do you measure or determine that the barrels life is over. Rifling inside is crisp and clean. Thanks

Ken’s Answer:

Wandering rounds could be from many things. Inspect the bore for rounded over lands and grooves. Check the throat area for “salt and pepper” light pitting and rounded over land that extend forward from the throat. Check the crown, but since it shoots the first shot well then starts to wander, I doubt the crown is to blame. Before spending time and money on a new barrel I like to remove all the other variables first as they are a lot less expensive. Make sure the scope is still good. Make sure the mounts and rings are installed correctly. Make sure the trigger pull is good. Bed the action correctly and float the barrel. Once all that is done shoot a group. If the problem is gone, then great. If not pressure bed the barrel and then shoot a group. (Pressure bed only a wooden stock). From the sounds of your description I would say it needs to be glass bedded. Ken


I am about to do my first SKS Trigger Job. After I do it can I send it off to you and have you check my work? What would the cost be on something like that? Do you do this kind of a thing?

Ken’s Answer:

Yes, I’ll check your work. It is best if we have the whole gun so we can check how everything fits and operates. On some guns for some repairs we would want to test fire as well. If it is just a check over and return, the cost would not be that much… if it is incorrect in some manner and you would like us to repair it then there would obviously be a fee for that. I don’t like to quote prices as they vary some depending on what we have to do to check things out and how long it takes… but I would imagine the cost would be in the range of $10.00 to $20.00 plus S&H. Ken


I was trying to check head space on a Winchester 721 when I remembered the extractor is the riveted ring style. This makes closing the bolt on the round with a “little feel” kind of tough as all I can feel is the extractor resistance. I am wondering if anyone else has a suggestion or technique. I am using the piece of tape on the back of a round approach. Along these same lines, I am wondering the best way to check head space on a semi auto action that uses a rotary bolt design. I am thinking of the M1 Garand, M1 Carbine or even an AR. With a bolt action I have the ability to feel the bolt as it locks up, but in the rotary style bolts I am not sure how to know if it is completely closed and if it is tight or loose. Maybe this is a good topic for the Friday night Web Classes?

First Answer came from GCA member Doug Charette:

For any of the Remingtons, I slip the gauge under the extractor and hold it there as I shut the bolt. The action really needs to be out of the stock for this. For the semi-autos, operate the bolt by hand, not with the action spring. With a AR, it’s easiest to remove the barrel from the upper.

Ken’s Answer:

Right on Doug, I don’t believe I can add much. I don’t remove the barrel on the AR’s I just close the bolt and examine where everything lines up then when the gauge is installed the bolt should not rotate as far… just like a bolt action rifle. Ken


Any advice on switching out barrels for a S&W revolver N Frame 44 mag? I ordered a receiver wrench from Brownells and I have a universal barrel vise. This will be my first time, I know the concept of doing but I want to hear y’alls advice before I make any first time mistakes.

Ken’s Answer:

Soak it well with penatrating oil. Make sure the frame and barrel are snug in their vice/wrench. Go slow. Don’t get discouraged. The S&W’s usually… USUALLY… come apart easier than the Colts and again, usually with less bending of the frame. Ken


Thank you sir. And the installing of a new barrel? Just measure the threaded portion and remove what I need to make the barrel and sight straight when it is fully installed?

Ken’s Answer:

I screw the barrel in before I do anything else to see if it will screw in. Then to see how close to indexing it is. Then I take it out and do what ever machining is needed to make it index and fit correctly. Ken

19 Responses to Gunsmithing Q&A with Ken Brooks

  1. I’m with Ken on checking headspace on an AR (leave the barrel on). I do take out the recoil spring so I have full control of the bolt. Also, if you are checking a 5.56 (or .223), buy a set of gauges. It is so common, you will use them often. And it is quicker than tape.

  2. Ken, I disagree with you only bedding a pressure point on a wooden stock.
    I have a Remington 710 in 270 Win factory equipped with a synthetic stock that would not shoot a group less than 6″ (six inches)at 100 yards. After pressure bedding the tip of the stock: this gun will consistently group around 3/4″.

  3. Or just buy a laminate stock from Boyd’s….glass bed the action in using Devcon(I find that pillar bedding isn’t usually necessary given how hard the laminate stock material is)and rid yourself of the wood stock.

    With shipping….it would be $135.00 well spent. This has saved me money in the long run (And the money that is wasted on pricey ammo whether factory or handloads )not counting the aggravation and wasted time on dealing with poor shooting rifles.

    Then again…I’ve seen lots of scopes that wouldn’t hold zero and you’d be throwing lead all over the target no matter how well a scope was lined up and mounted correctly….including the famous Leupold’s….too many times from someone placing too much stress on the scope from misaligned scope rings/etc.

    I’d also ask you what is the purpose of use for the rifle…one inch groups for a hunting rifle is still rather accurate and use three shot groups testing for the 264 WinMag and do not over heat the barrel though it reads that this is the shot group you are using…..just my suggestions.

  4. I would look at the scope first, if as you say the rifling is sharp. Second Limb saver makes a device that removes most of the harmonics from a barrel. I have had more than one scope go bad and do really weird things to my shooting. GRIZZ

    • Yup…”Deresonators”…I found that not only do these simple slip on devices really dampen the harmonics of the barrel…these have saved me money not having to work up various loads for a rifle thinking that a particular loading wasn’t cutting the mustard. After all…if using a deresonator on a hunting rifle enables us to shoot accurately…these may not look so cool (And they don’t really!) but the end results is what counts of course.

      I have one on a Savage 30-06 flat top that without one…I’d have to restock/rework…not a bad shooter for a $15.00 + – investment of a deresonator. God that rifle is ugly but simply shoots too well to do anything for looks to it. And I’ve taken a lot of animals with this butt ugly Savage to boot! Go figure.

      But a paying customer probably wouldn’t agree to live with a deresonator.

  5. Ken
    I picked up a set of extended take-down pins for my AR but I can’t seem to figure out how to remove the OEM, front pivot TDP, because of the detent pin already installed. (meaning, how do I get the spring and detent out)..any suggestions?
    Henry J

  6. The easiest method I have found is to use a dental tool to compress the detent so it is free of the groove in the take down pin and rotate the pin so the detent no longer lines up with the groove, then pull out the pin. I then use the same tool to compress the detent when installing the new pin.

  7. Brownell’s makes a tool for depressing the detent so you can rotate the pivot pin; similar to the dental pick, but better (specifically designed for the task). Also, most pivot pins I’ve seen have a small hole drilled in them near the left end. Pull the pin out to the right as far as it will go, and the hole “should” line up with the detent. Then just stick a punch through the hole to depress the detent & spring and rotate the pin.

    • Re-reading your post I see now what you were talking about…pulling the TDP out to the right and inserting a small punch in that hole seems to be a lot easier (and safer) then using a thin blade. Thanks for your idea!!!!!!!

  8. I do have two different tool sets for the installation of the detent pins but that’s just for installation. Getting them out is a whole different animal. I used a thin Exacto blade wedged in between the take-down pin and the detent…pushing the detent back with the blade allowed me to pull the take-down pin right out. Unfortunately, on one of the tries, the blade slipped and sliced a nice gash in my left index finger.
    I should take some pics to show how nice these new take-down pins are. :o)

    • No… I meant Brownell’s makes a tool for removing the pivot pin. SKU# 080-216-010

      For anyone interested, the installation tool is SKU# 080-216-011… and if you want both you can order them as a set: SKU# 080-001-159

  9. HI: I need a suggestion on how to loosen the injector on a S&W Shield
    3.1 bl. I bought for my wife, but she can not pull it back.
    Someone told me if a I run 2 or 300 rounds through it, it would loosen up. Do you have any suggestion, I would appreciate it very
    much. Thanks Russ

    • Have her hold the grip in her hand and the top of the slide with her other hand, then push against the gun with both hands, i.e. push the grip to her left and the slide toward her right. Using both hands should enable her to chamber a round. If not trade the S&W Shield for a S&W J-frame revolver.

  10. Hello Ken…I’ve got an interesting rebuild…an old B78…after finding a new forearm and ejector managed to reassemble the concoction after leaving it disassebled for 3 years…I would value an AGI video for the trigger job on this one!!!…However , in testing the firearm it worked fine for 10-20 openings, checking a manual pull back of the hammer, I then managed to dislodge the hammer springs and pins which are now still in the trigger assembly slots but between the block and the upper receiver….don’t want to cut them….what do you think…
    Brian Deezar
    AGI Alumni

    • Brian–other readers may have an answer for you, but if you want Ken’s advice you might get a faster answer by contacting him directly at his shop. He is always keen to help AGI students and graduates. His contact info for PISCO Gunsmithing is here.

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