Another Kimber project rifle

[Nature Boy]

It would be a pretty boring hobby if everything worked 100% of the time

 

[horsemen61]

It would be a pretty boring hobby if everything worked 100% of the time

Yeah that would be awful

 

[MCMXI]

I installed the titanium bolt handle yesterday and had to relieve a little material from the bolt slot in the stock since the shaft of the new one has a different (larger) profile and was scraping the rear of the slot and sticking. I wanted one of the Ti bolt handles without flutes but they're currently unavailable so will swap it out once they're back in stock. I also figured out that Accuracy International AW magazines might be a possibility for this build and that would be my preference given the shorter length when comparing the 10-round versions. I need to do some tinkering but if I can figure out the feedlip/follower situation it might work. The photos below show both the standard 10-round AICS magazine and 10 round AI AW magazines in the rifle. Both 10-round mags will hold 7 rounds of 6.5 PRC. The 5-round AICS magazines will hold 3 rounds of 6.5 PRC. The 6.5 PRC has an OAL of 2.955" so MAGPUL mags won't work, and any AICS or AW mag can't have the stiffener plate in the front. AW mags allow for a COL of 2.980", AICS mags without the front plate allow for an OAL of 2.985" so both will accommodate Hornady factory 147gr ammuntion. I also added some nylon spacers to set the comb height for quick/easy on/off installation because the comb has to be removed in order to remove the bolt.

So at the moment I still have some things to figure out but this project is moving along nicely. Now that I know the accuracy potential is there I have plenty of motivation to wrap this project up.

Here are some better photos.

 

[horsemen61]

I installed the titanium bolt handle yesterday and had to relieve a little material from the bolt slot in the stock since the shaft of the new one has a different (larger) profile and was scraping the rear of the slot and sticking. I wanted one of the Ti bolt handles without flutes but they're currently unavailable so will swap it out once they're back in stock. I also figured out that Accuracy International AW magazines might be a possibility for this build and that would be my preference given the shorter length when comparing the 10-round versions. I need to do some tinkering but if I can figure out the feedlip/follower situation it might work. The photos below show both the standard 10-round AICS magazine and 10 round AI AW magazines in the rifle. Both 10-round mags will hold 7 rounds of 6.5 PRC. The 5-round AICS magazines will hold 3 rounds of 6.5 PRC. The 6.5 PRC has an OAL of 2.955" so MAGPUL mags won't work, and any AICS or AW mag can't have the stiffener plate in the front. AW mags allow for a COL of 2.980", AICS mags without the front plate allow for an OAL of 2.985" so both will accommodate Hornady factory 147gr ammuntion. I also added some nylon spacers to set the comb height for quick/easy on/off installation because the comb has to be removed in order to remove the bolt.

So at the moment I still have some things to figure out but this project is moving along nicely. Now that I know the accuracy potential is there I have plenty of motivation to wrap this project up.

Here are some better photos.

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Now that’s what I’m talking about looks really really nice! Great Job @MCMXI !!!!!

 

[MCMXI]

@horsemen61, thanks. I just noticed that I have a duplicate image above. I'll fix it when I get back home.

I'll shoot a couple more groups with the 147gr then a couple with the 143gr ELD-X before I start load development. The barrels are going back to Proof next week to be engraved which will take a few days I'm sure. I can still handle a few things when the barrels are out.

 

[LoonWulf]

Digging it!

 

[Nature Boy]

I’ve always liked that desert camo pattern

 

[MCMXI]

I’ve always liked that desert camo pattern

Me too!

I received a reply from AREA 419 re the brake. I guess they missed the point that the adapter was the same and unchanged for both scenarios. I'll shoot it on two other rifles, or just one if it's great from the get go. I'll make sure that it's seated on the adapter properly too.

"this is a weird situation and not something we're used to seeing. It looks like there is a clear indication that the brake is doing something strange. My first worry would be an issue with the brake or adapter. Something not concentric or anything like that affecting accuracy, which we can absolutely swap out and hope to get you taken care of. The other thing I will say, just to check all the boxes, is to double check nothing weird happened during install. Things such as long thread length not allowing the adapter to seat properly on the shoulder, over torquing the adapter, or the brake body not being properly seated on the adapter. One thing we've seen before, in regards to the last point, is brakes not being properly seated on the taper before tightening the collar.

All that being said, I'm interested in what you find when trying the brake on different rifles. Like I said before, this is very strange, the brake should not affect accuracy like you are seeing under normal conditions. Minor effects to barrel harmonics can require slight load tweeks to get optimal accuracy, but again, you seem to be experiencing pretty drastic changes. Let me know what you think, and we are open to taking care of you however you feel works best, if we just want to try sending a new brake out to you, thats what we will do, just let me know!"

 

[MCMXI]

I sent a reply to AREA 419 this afternoon and received another follow-up email. I want to say that not only does AREA 419 make excellent products, their CS is excellent too. I've had no need to contact them up to this point but I really hope that I didn't seat the brake properly when I shot the other day. Regardless, they've been very responsive and I want to provide them with good data.

"Another thing that has happened before, but it has been very very rare, is there is something asymmetrical in the milling of the ports that’s imparting some odd turbulence inside the brake.

When designing the brake, we never tested on 6.5 PRC (it didn’t exist yet) but we did shoot a fair amount of 6.5 SAUM and 300 Norma (through their appropriate calibers). We saw no change in the way the brake impacted accuracy based on the magnum/standard change.

Let us know, could be something as simple as a bad port in the brake."

 

[MCMXI]

I did some shooting today to test the AREA 419 brake on a different rifle and I think that AREA 419 will most likely kick me off their Christmas card list! I'm pleased though because it was a learning opportunity. I got to shoot which means practice, the brake seems to be just fine although the blast is obnoxious, and I was able to test some 6.5x47mm Lapua rounds that I'd assembled for an ex-girlfriend's rifle (her ex-husband's recipe) and was impressed by how well they shot in my Accuracy International AXMC.

I cleaned the tapered cone and oiled the threads on the universal adapter and was careful to make sure that the brake was seated properly before tightening the locking collar. I shot a 5-round group with the Omega attached, then shot two 5-round groups with the brake, and finally one more 5-round group with the Omega. I was aiming at the center of each diamond with the exception of the last suppressor group. For that group I aimed at the bottom of the diamond to get two comparative groups on the same diamond.

So here are the results. I'll shoot the Kimber 6.5 PRC with the brake attached this weekend and be sure to install the brake properly. It's entirely possible that I messed up and will know for sure soon enough. I will state emphatically that there's a significant difference in the shooting experience with the brake vs. the suppressor. I much prefer the suppressor which doesn't blast me in the face and seems to result in less felt recoil.

First group with the Omega



First group with the brake



Another group with the brake followed by another group suppressed

 

[LoonWulf]

I did some shooting today to test the AREA 419 brake on a different rifle and I think that AREA 419 will most likely kick me off their Christmas card list! I'm pleased though because it was a learning opportunity. I got to shoot which means practice, the brake seems to be just fine although the blast is obnoxious, and I was able to test some 6.5x47mm Lapua rounds that I'd assembled for an ex-girlfriend's rifle (her ex-husband's recipe) and was impressed by how well they shot in my Accuracy International AXMC.

I cleaned the tapered cone and oiled the threads on the universal adapter and was careful to make sure that the brake was seated properly before tightening the locking collar. I shot a 5-round group with the Omega attached, then shot two 5-round groups with the brake, and finally one more 5-round group with the Omega. I was aiming at the center of each diamond with the exception of the last suppressor group. For that group I aimed at the bottom of the diamond to get two comparative groups on the same diamond.

So here are the results. I'll shoot the Kimber 6.5 PRC with the brake attached this weekend and be sure to install the brake properly. It's entirely possible that I messed up and will know for sure soon enough. I will state emphatically that there's a significant difference in the shooting experience with the brake vs. the suppressor. I much prefer the suppressor which doesn't blast me in the face and seems to result in less felt recoil.

First group with the Omega

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First group with the brake

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Another group with the brake followed by another group suppressed

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oops' happen, here's hoping it works well on the PRC, otherwise you'll at least know there's some weird interaction there.

 

[MCMXI]

oops' happen, here's hoping it works well on the PRC, otherwise you'll at least know there's some weird interaction there.

It will be interesting for sure. I only bought the brake for testing purposes and don't plan on using it for anything else.

 

[Nature Boy]

the brake seems to be just fine although the blast is obnoxious,

The only brake I have on a hunting rifle is a hellfire and I wonder if they aren’t all obnoxious, particularly when hunting from a box blind. The primary reason I use them is for load development at the bench. I still hunt with it but in a confined area they will ring your bell

 

[LoonWulf]

The only brake I have on a hunting rifle is a hellfire and I wonder if they aren’t all obnoxious, particularly when hunting from a box blind. The primary reason I use them is for load development at the bench. I still hunt with it but in a confined area they will ring your bell

Some are worse than others, but ive never shot a braked gun that wasnt horribly offensive.

Large port side venting are noticeably worse than radials also. Personally i try to get some kinda hearing protection in before firing, and have started carrying a set of electronic ear muffs in a side pouch of my hunting bag or on the dash of my truck.
Only animals i shot since doing that tho I didnt remember the muffs.

 

[MCMXI]

Large port side venting are noticeably worse than radials also.

Yep, I'd certainly agree with that. I try to shoot everything suppressed these days if I can. We can use suppressors for hunting in MT so there's really no reason not to. I've lost count of how many suppressors I have now but I still want more. Basically I'd like to have a dedicated suppressor for every rifle but that will mean getting some barrels threaded. I don't think I'll be threading the two Lee-Enfield No4 Mk2s though ....

 

[LoonWulf]

I wish we could even own a suppressor out here, really the only NFA item I want.

 

[Legionnaire]

I'm enjoying the updates. You have me interested. I have an Area 419 Hellfire on my Bergara HMR Pro in 6.5 PRC. I haven't shot it much yet, but first couple groups were .5 and .6 MOA. I never tried without the brake ...

 

[MCMXI]

I'm enjoying the updates. You have me interested. I have an Area 419 Hellfire on my Bergara HMR Pro in 6.5 PRC. I haven't shot it much yet, but first couple groups were .5 and .6 MOA. I never tried without the brake ...

It's entirely possible that I didn't have the brake installed properly, and the results above shooting 6.5x47 Lapua seem to point in that direction. I'll try to shoot the PRC tomorrow, maybe groups of 147gr ELD-Match and 143gr ELD-X suppressed followed by the same with the brake.

 

[MCMXI]

Update on the magazine:

The Accuracy International AW magazine won't work so it'll have to be the AICS magazine. I'm having to modify the feedlips to get the AICS magazine to work properly but it's looking good. I'm thinking about modifying the magazine release to add a paddle on the right side so that I can release the magazine by pushing the paddle to the right side of the trigger. Currently the trigger guard obscures the magazine release.

 

[MCMXI]

I have a 6.5 PRC GO gage and used it to set up (zero) a Redding Instant Indicator- Case Comparator. The GO gage is minimum SAAMI and the bolt on the rifle closes with a hint of resistance. I measured all 16 fired cases and the majority were at zero i.e. the same as the GO gage with four at +.0005"~.0010" which implies that the chamber headspace is very close to minimum SAAMI. Nice!

The barrels are going back to Proof tomorrow to get laser engraved with 6.5 PRC and I'm going to ask them to engrave (1-7.5) too.

 

[MCMXI]

I shot another 16 rounds today including some handloads using US 869. I wanted to get an idea of the velocity that I might expect as well as confirm the factory velocity for the 147gr ELD Match load. Hornady claims 2,910 fps for their 147gr but I'm not even close at 2,777 fps which is 133 fps slower, and that's shooting suppressed!! I began by shooting three rounds of factory 147gr ELD-Match followed by 65.0gr, 66.0gr, 67.0gr and 68.0gr of US 869. I had one round of the 66.0gr load that wouldn't chamber so only two shots for that load. I didn't make any scope adjustments and the high shot on the 65.0gr target was the first of four. I made up four of that load to check scope zero since I had no idea where it would go compared to the factory stuff. When I realized that it was close enough I decided to shoot four rounds for that group. Changing powders can have weird effects for a shot or two. I guess I'm trying to say that the group would probably have been a lot better if starting with a clean barrel.

QuickLOAD was very close on predicted velocities for these loads, and that was using the standard Ba value. 66.0gr to 67.0gr resulted in accurate loads with similar velocity to the factory stuff. I can't get much more than 68.0gr of powder in the case so I guess if I'm to use US 869 I'll have to settle for a factory like load. The barrels are going back to Proof tomorrow so I won't be able to shoot for a few days, and maybe longer depending on their work load.

Who would have thought that a 4-shot 0.829 moa group could look so bad! I was dealing with some mirage by the last group but every shot felt good so no excuses there. Clearly not a good load at the current COL.

 

[LoonWulf]

I was something like 5 or 6gr over max with everything besides the new IMR Endurons before getting to velocity and pressure.

 

[MCMXI]

I was something like 5 or 6gr over max with everything besides the new IMR Endurons before getting to velocity and pressure.

Interesting. I didn't have any pressure signs today so I'll try to work up to compressed loads with US 869 to see what happens. It's a very fine ball powder but I'm not sure how much more I can get in the case. Looking through my notes for the 6.5 PRC Bergara barrels, I had no problem getting to 3,000 fps with H1000 and 147gr ELD Match bullets. Factory 147gr was 2,726 fps out of the Bergara 24" barrel.

 

[LoonWulf]

the only powder i tried faster than Retumbo or 7828... was 4955, and I damn near blew myself up with what one. Its one of the reasons I REALLY suggest starting at starting with the Endurons.
Retumbo was like 4-5% compressed, 7828 was right at 100%, and RL-25 was .....i forget, i still have some of those rounds ill go check.

I just went and looked at Hodgdon site...they don't have 4955 listed for anything 120+
Im 99% sure i was using Hodgdons data.

 

[MCMXI]

Was this in the M18 that @troy fairweather got from you?

I'm very pleased with the precision at the moment... couldn't be happier in fact, but I would like to get some more speed with the 869 if I can. As the saying in Hawaii goes ... if can, can ... if no can, no can.