I think the spigot mount gives you the most versatility. You will need a rail section for the mount and the rail adaptor for the bipod, but you can install and remove the bipod with no tools or small parts to lose.

The Arca-Swiss mounting system has been around for many years and I was vaguely aware of it for photography purposes, but I’ve only recently noticed its adoption by shooters to mount accessories and to mount rifles directly to tripods. I also note that more manufacturers are offering Arca-based accessories for shooters. Beyond that, though, I don’t know much about the system myself, so I would also be interested in any discussion and advice current users have to offer.

Added: The below photo shows a KRG with a “spigot” mount for the bipod. It uses a Picatinny rail section for my QD mount to attach to, but it appears that the KRG Arca spigot mount would be the same except designed for an Arca clamp.

There are a couple of advantages to a spigot mount in front of the forend of the stock. In theory at least the farther forward the bipod is mounted, the less any movement by the shooter’s body affects point of aim. In addition, it leaves the bottom of the stock unencumbered for whatever else we might want to do with it.

The alternative is to attach a long Arca rail to the bottom of the forend and that would have its pros and cons. The big pro is that it permits attaching the bipod or other accessories such as barrier stops to any point along the rail we wish rather than at one fixed point. If the shooter is trying to engage moving targets, as in certain competitions, the rifle can be panned through a larger arc more easily if the bipod is attached farther to the rear. Depending upon its configuration the rifle could also be mounted on a tripod with Arca head, and it might be possible to balance it in position without any other support; because the spigot mount is so far forward, that wouldn’t be possible with it.

The disadvantage I see to the long Arca rail on the forend is how the rail would affect shooting from certain surfaces, but more important, how vulnerable it might be to damage if we’re resting the forend on something like a metal fence rail or if the gun is being banged around. Perhaps there are protective covers that could be put on the rail, but I haven’t researched that.

I never considered the Arca mounting system before now and might change my mind in time, but if I had to make an immediate decision right now, I’d still choose the spigot mount over the long rail for the type of shooting I do.

The spigot is a better choice over the extended rail for most shooters as it is used strictly as a bipod mount. The extended Arca rails can flex a little and are of little use unless you plan on clamping in on a tripod or compete in matches and need the ability of sliding the bipod back to obtain a shooting position on a small surface or use as stop against a barricade.

Personally, I don't compete anymore so Arca rails do little for me. I regularly use a tripod in my shooting and just use a rear bag on a table for distances out to 1200-1300 yards. If I'm shooting longer distances, say 2000 yards, I will clamp in to a short 4" Arca rail mounted at the balance point of the rifle, just in front of the magazine well

For most shooters who don't compete, the picatinny rail system is more convenient as you can use 1 bipod on several rifles, including ARs, for less cost. YMMV


Sigfreund: Nice example of a rifle using a KRG chassis with a spigot mounted bipod.

Thanks, Sig Marine, for your comments. That’s exactly the sort of thing I appreciate here.

To say I am happy is an understatement...I love this stock and yes it is my first “tactical” stock but I made this switch for just over $300.00 because I had the Harris Bi-pod already....This beast weighs in at 12lbs and 5oz (unloaded)...In any case I wanted to thank everyone who provided me guidance, recommendations, offering of support and handling/shooting their set up because I would not have arrived here today with what I have and at this cost without this groups help....Here are a few pictures of the before and after...Also I went with the Harris Direct Mount adapter which makes the bipod a semi permanent item but that is ok because I do not have any other rifle that uses it today. This direct mount is significantly stronger than the standard mount because you insert the main body of the Harris bipod into a sleeve on this mount that is permanently mounted to this stocks aluminum framework. Attach my SilencerCo Omega and I am ready for the range. I am going hold on to my factory stock for now to insure I like this set up....Mark

Looks good.
Keep us posted on how it performs for you.

Nice rifle! Hope to see some groups from it soon. I always like finishing new projects.

Tony.

Saweeeeet!

Enjoy the new chassis and, as mentioned, don't forget to post a range report.

Looks good!

12/19/2020 Range Report

Conditions - Overcast and 57F
Bullets - 168 BTHP - Factory and Reloads
Suppressor Used - Yes - SilencerCo Omega

Was only able to shoot out to 100 yds but today was a blast...Tried several different reloads all with a Hornady 168 BTHP bullet on top. I also shot a couple of groups using Federal Gold Match 168gr BTHP and was surprised with the results...I think the greatest part of this new stock system is being able to use removable mags. Now to purchase a couple of rear shooting bag rests to help me hold this beast on target better. Today I used four 10lb sand bags to lock the rifle in place and learned after the first cold/clean bore shot that I still need to have a little pressure on the forward portion of this rifle or it will lift the bipod legs off the shooting bench....

In any case I will get back out in a few weeks when the 200yd range opens back up to see what I can do at that distance. One thing you will see in todays range pictures - I did NOT adjust the scope in any way today. I just wanted to see how it shot with the new stock and bipod. I will dial it in when I shoot it at 200yds.....Thanks again to everyone for your recommendations related to getting this type of stock system. This thing is really fun to shoot and the pad on this stock made for a very pleasant day of shooting. Now to figure out how to stop my heart from beating just before I am ready to pull the trigger....Mark

Cold and Clean Bore and Suppressor First two shots



Then the fun began. Here are the best two groups for today out of 8 different groups (some were 3 shot and some were 5 shot groups and one was a four shot group) I shot....




This is actually a FOUR shot group - NOT a five shot group as it is written

Nice work...and thanks for sharing a range report!

quote:

Originally posted by sigarmsp226:
Now to purchase a couple of rear shooting bag rests to help me hold this beast on target better. Today I used four 10lb sand bags to lock the rifle in place and learned after the first cold/clean bore shot that I still need to have a little pressure on the forward portion of this rifle or it will lift the bipod legs off the shooting bench....

In any case I will get back out in a few weeks when the 200yd range opens back up to see what I can do at that distance. I will dial it in when I shoot it at 200yds.....Now to figure out how to stop my heart from beating just before I am ready to pull the trigger.

Nice shooting. Looks like the new stock will work out well for you.

1) Bipod hop on a hard surface is common with a Harris. Harris bipod legs are fixed, and thus they must move backwards as the rifle moves backwards from recoil. There's no way to eliminate all recoil from a 308. You can reduce it with a brake, and mitigate its results by holding the rifle's buttstock firmly into your shoulder. Even if the rifle moves backwards only 1/4" during recoil, the bipod's feet must also move rearward 1/4". If the feet are resting in soft dirt, there may not be any hop. If the feet are on a hard surface, hop likely occurs.

In all likelihood, your rifle moves 3/8" to 1/2" to the rear during recoil -- if your technique is good. By that, meaning that your scope's crosshairs remain within .4 mils or less of your Point Of Aim throughout the recoil cycle, then your technique is pretty good. If your crosshairs end up being 1 mil or more away from your POA after the recoil cycle is over, then your rifle probably moves more than 1/2" to the rear.

2) There are many types of rear bags. From small to large. Light fill and heavy fill. Many shapes -- from traditional bags and cubes to multi-armed thingies to shoot from barriers. If you've been using sand bags, something heavier might be in order. The Game Changer from Armeddon Gear might be on your short list. There are many lighter-fill bag options from Wiebad.

3) Assuming you zero at 100 yards, expect about .5 mil drop going out to 200 yards.

4) The best way to eliminate your heart from beating just prior to taking the shot is by dying. I suspect follow up shots might be a challenge, however.

The myth of shooting around, between, across, during, before, or after the heartbeat needs to...die. I suspect it came from shooting in slung positions, where the sling is pressing against a major artery in the shooter's support-side upper arm. Yeah, I've done that more times than I care to admit. And yes, I can feel my pulse in my sling's cuff. But there's enough wobble from other factors in such style of shooting that feeling your own pulse is just about the least of your aiming difficulties.

You're shooting from prone with bipod and bag support. Your heart is going to beat on its own accord, and it shouldn't affect your accuracy. The accuracy issues you should be concerned with include:
- align the gun to the target, then align your body to the gun
- develop a position with a good natural point of aim
- break the shot during your natural respiratory pause -- don't hold your breath
- break the shot without disturbing your sight picture
- follow through on the shot

quote:

Originally posted by fritz:
The myth of shooting around, between, across, during, before, or after the heartbeat needs to...die.

Wait, wut?

I first read the “shoot between heartbeats” advice in a book by a former military sniper. If anyone can do that he must have a very low heartrate because when I’ve attempted to do that, the only way I could break a shot in that tiny interval would be to snatch at the trigger. That would of course be very detrimental to precision shooting in itself, and I really don’t understand how it would be possible. Long ago when I was involved in smallbore shooting, I used a tight sling on my support arm and that helped with pulse movement, but I didn’t try to time anything between beats.

Fritz - Thanks Sir for the feedback, recommendations, and advice. I will be heading over the the Armageddon site this evening to purchase the bag you recommended. To your other points I have a lot to learn especially related to body and gun alignment. There is a small group of long range shooters in my gun club, several with military backgrounds in long range shooting and my plan is to go out the next time they shoot to watch and learn.

I sincerely appreciate all of the information you posted. This is a new adventure for me and I think I have the right rifle to see it my interest continues. The good news is a have about 200 pieces of 168 BTHP Hornady bullets so I have a starting point.

I think for now I will focus on the basics that you identified and worry about the bullet portion of this situation at a later time...If I can learn good technique’s the bullet I use can be determined later....The rifle is capable but I need to learn how to manage it without the use of four 10lb sandbags...

This is going to be fun, frustrating (I am sure) and an opportunity to learn...Thanks again - Mark

quote:

Originally posted by SgtGold:

quote:

Originally posted by fritz:
The myth of shooting around, between, across, during, before, or after the heartbeat needs to...die.

Wait, wut?

I get it – the concept of shooting between heartbeats has been taught for a long time. But things change.

Let’s start with the timing. It’s my understanding that the average heartbeat occurs in roughly 1/10 of a second. Which leaves the heart muscle in a more-or-less resting state for the rest of the time. Assuming a nice slow resting pulse of 60 bpm, that leaves 9/10 of a second for no blood flow from the heart. However, the blood doesn’t move instantaneously throughout the body. There is some delay throughout the body before the blood reaches it. I don’t know the amount of time, but the delay is there. Before my last surgery, the medical techs hooked up up a couple dozen sensors all over my body, and they showed me on the EKG printout the slight timing difference of the pulse in my extremities.

But most of us don’t shoot with a pulse rate of 60. Something closer to 90 is realistic if we’ve been moving around a bit. That’s a .67 second cycle, with maybe .57 seconds of rest – not considering the blood flow timing. I do not believe the heart pump cycle time changes much as our overall pulse quickens. With ever more movement and some adrenaline added, a pulse of 120 is reasonable. That produces a cycle of .5 seconds, with maybe .4 seconds of heart rest time. I’ve been in competitions and training where we ran hundreds of yards between stages with pack and slung rifle. Pretty certain pulse rates of most competitors for their first shots were noticeably above 120.

I heard from a buddy who used to drag race cars that our mental/physical reaction time is generally .18 to .20 seconds. If a person tries to time the trigger pull, that delay must be figured in, too. Then there’s the time required to engage the trigger finger through the trigger press, then break the shot.

****
Earlier this month I attended a helicopter rifle assault course at the Rifles Only (”RO”) facility in Kingsville, Texas. The day before I arrived, RO just finished a 10-day precision rifle course to train 7 Marine snipers. The Marines were gone, but the two contracted assistant instructors stayed on for another day. These instructors had earlier worked with the Marines on field courses, and tagged along to assist RO and to continue evaluations. IMO the RO facility isn’t the best for stalking training, but I suspect some of the earlier field exercises were dealt with while shooting at RO.

The primary field course instructor hung with us helo students during the first day of our course. Our first day involve a fair amount of classroom work – fundamentals of marksmanship, dry firing, safety overview. Much time was spent on developing & maintaining a Natural Point of Aim (“NPA”) while either the shooting platform or the target was moving. When we discussed breathing issues, one student brought up the effects of pulse. Jacob Bynum – who owns RO – said they don't consider pulse in the accuracy equation. Privately, I asked the field course instructor if the Marine sniper training considered pulse – he replied that they did not.

Years ago I attended a RO course in Colorado, where Jacob had a camera system hooked up to scopes on an AR15 and a bolt action 308. The camera sent video to a laptop, and we students watched what was going on when Jacob fired. Jacob demonstrated the sights movement under recoil for brake vs. no brake. For good technique vs. poor. For reticle movement in the breathing cycle. For reticle movement when slung tightly, with Jacob’s pulse hammering in the sling’s cuff. By far the greatest reticle movements before and during the recoil came from breathing cycles and poor shooting technique. Reticle movement from pulse was so small that we often could not tell it was pulse or other factors – breathing and arm muscle contractions.

****
RO is a significant trainer for precision shooters in the miltary, contractors, LEOs, and alphabet agencies. RO also trains a bunch of civilians involved in competition, hunting, and self defense. RO ignores the effects of pulse on accuracy. I’ve heard second hand from fellow shooters that other premiere schools do the same – such as Gunsite, K&M, Thunder Ranch.

On the civilian side of things, where we can use names, RO recently did a bunch of work with Regina Milkovich. Jerry Miculek has spent time at RO. To a lesser extent RO has worked with Terry Cross, Rob Leatham, and Bryan Litz. If these names are unfamiliar, a quick Google search will reveal their accomplishments with firearms.

****
A few years ago I attended a RO course in Colorado, where Nick Irving was a guest instructor. Nick was a recently retired Ranger sniper, who had 30-something kills in the sandbox. Nick is one of the more accurate shooters I’ve been around. First time testing both my 308 and 6.5CM bolt action rifles, he shot 5-round groups at 100 yards that measured no more than .2”, when he wasn’t warmed up. On a dare from the other instructor, Nick placed a first-round hit, near the center of an IPSC target at 750 yards, with a KAC SR-25, using FGMM 175, from a rice paddy squat, with 5-10 mph crosswinds.

This RO course involved a lot of alternative position shooting, and movement between positions. At times we ran up to a few hundred yards prior to shooting drills. We students asked if we should considered breathing, pulse, NPA, rear support, or whatever to stabilize the rifles. Nick said he didn’t bother to time shots with his heart rate. Sometimes it was challenging to even deal with breaking the shot at the bottom of the breathing cycle.

Nick stated that while deployed, he was primarily concerned with what the target was doing. He went with the idea that his prior training on the fundamentals of marksmanship would take care of themselves when he broke the shot.

I was actually agreeing with you but I enjoyed the write up on precision rifle techniques. When shooting the rattle battle you run two miles or do some kind of PT just prior to the match so yea, good luck shooting between heart beats. I think teaching the natural respiratory pause, and modifying that to suit the conditions of the course of fire is a much better way of controling that variable.