Sounds like it will fill my needs nicely, i already figured on loosing a couple hundred rounds of barrel life, it sounds like Nosler anything is hard on barrels anyway. But getting some extra velocity out of a shorter barrel is what i wanted. I found Berger 208s, hoping to get them up to 3000 with a 22" barrel.
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+P Throating
- Thread starter chetraguse
- Start date
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The Allen Mag is an ego trip for sure. I love mine. Never had to do more than a cold bore shot for hunting. It'll last a lifetime the way I use it. Stuff happens when you hit something with it for sure. I went with the 400MOD harder stainless from Bartlein, which is a great option for stuff like this.
Alex Wheeler
Well-Known Member
The stepped throat originated from 50 BMG BR competition. It does work. But from what I have seen accuracy life is shorter and falls off faster. The throat is critical to accuracy, Im sure you have heard of setting a barrel back. You could just throat it some to sharpen the lead and get the same result. Personally, accuracy is more useful to me than speed. I have gone full circle to stuff that shoots really small.
Fiftydriver
Official LRH Sponsor
Not caring is not correct. If you use these extreme rounds as you would any other chambering you will go through barrels quickly. However if you understand their strengths and weaknesses, you can use them to exploit their fullest potential and not use them when its not needed.
i talk 10 customers out of my wildcats for every one i build, simply because they do not need one for their goals. Or i will explain how another of my wildcats or another chambering will serve them much better. I never push my products on anyone, but instead offer a meaningful conversation with the customer to learn what they want to do with this new rifle and then continue the conversation to make sure!
one would never use a top fuel 11,000 hp dragster to go pick up a gallon of milk, could not thing of a worse use for one, but to cover a 1/4 mile strip as fast as possible, could not think of a better use.
some common sense needs to be used in rifles as well. My first question to potential customers is "what other rifles do you own". This tells me the flexibility they have in their equipment list.
if they tell me this will be their first and only big game rifle, i would rarely ever recommend one of my wildcats.
if they tell me they own something like a 6.5 creedmore and a 300 win mag for example But want a true hyper performance rifle, then yes, one of these such as a 7mm Allen Magnum would make much more sense.
to that same point, i would explain in great detail how the 7mm AM should be used. If your hunting whitetails in riverbottom country, use the creedmore, if your hunting elk in heavy timber, use the 400, if your going on a pronghorn hunt but also will have a few days of prairie dog hunting, take the creedmore and the 7mm AM.
point being know the strengths and limitation if all your rifles and use them appropriately.
same goes with these throat designs. There is no question they increase performance and also reduce throat life. Those are pros and cons that must be weighed. I did not feel it was worth it to my customers as my wildcats are designs with the ability to produce extreme performance on their own and still use a long accuracy life throat design.
Shawn decided to offer his throat as an option for any chambering As a performance boosting option which it certainly is.
again, understanding their limitations are critical to get the most out of them. How these throats are used will go a very long way to how long their lifes are. In honesty i would not recommend even three shot strings with them, or as few as possible. Practical field shooting would be the very best method.
i was told time and time again i would burn out the barrels on my 7mm AM rifles before ever finding a good load. This turned out to be total BS. If someone shot one of my 7mm AM rifles like they would a 6.5 creedmore, you will use up your barrel very quickly, if you use it how i recommend it will last well over a decade of very hard big game hunting use or more.
my last test rifle in 7mm AM was used for a load of ballistic testing and load development. I then reserved it for use only for big game hunting and took 34 head of big game at ranges from 500 to 1050 yards, all but two being one shot kills. The two that were not were one shooter error not setting the rifle up correctly and clean missed on the first shot. The followup shot was a clean kill at 670 yards on an old whitetail. The other was a bullet issue. Tried a new bullet, pinned the shoulders on a mule deer at 780 yards breaking them both but not killing the buck. Took a follow up shot to kill that deer.
that was after 10 seasons of use. When i stopped shooting that rifle, the bore was So warn it would not shoot the 180 gr bergers anymore and they would often come apart in flight. However, it still shot the 160 gr accubonds and 168 gr barnes LRX into 1/2 moa groups. The hammer bullets were not yet an option.
even so, i installed a fresh barrel and sold the rifle. To my knowledge its still being used properly and hard with good accuracy.
use them right for their design and life will amaze you. Use them wrong and the wifes tails will continue to dog them but more because or misuse then anything to do with the chambering
Tumbleweed
Well-Known Member
Ok, so I've decided to chime in here with my experience with one +P throat. This is just sharing my experience and in no way trying to discourage anyone from going ahead with a +P.
Bob and Shawn Carlock re-barreled, chambered and +P throated and cerakoted my full custom Rem 700 300 RUM. The work was second to none and both Bob and Shawn were very personable and showed me around the shop when I picked up the rifle. I will very likely have them do more work for me in the future.
Barrel:
34" finished length Bartlein 5r 1:9 to 1:8 transitional twist 400MOD throated for 245 EOL Bergers.
Barrel break in didn't go so well, lots of copper that didn't seem to go away. After talking with both Bartlein and Shawn, I decided to stop cleaning and just go with it. Accuracy right off the bat was exceptional printing 5 side by side groups at 250 yards in the .1's to .2's MOA in load development. ES was typically around 20fps prior to barrel speed up. This was using RL33, ADG Brass and Fed 215M.
The barrel is typically cleaned down to bare metal and HBN coated every 50-70 rounds. I always keep a close eye out for a carbon ring and have not had an issue with that. I have never allowed more than 3 shots at a time (rare) and the barrel has never been hot. It is running some pressure.
Speed up finally happened at about 180 rounds where I backed my charge off by 1 grain to get back down to 3150fps with the 245. I attributed the poor break in and longer than normal speed up to the harder 400MOD barrel material. Accuracy was still very good and copper fouling was not causing any issues at this point. ES in this time frame was under 12 fps.
I did some testing with the 250 Atips (245 Bergers could not be found) and in my testing discovered that RL50 produced the absolute best velocity with the A-tips. I attempted to develop a load with the 250 and RL50. Initial results were great with 6 shots in pressure testing going into nearly the same hole at 100 yards. Seating depth testing at a low charge was producing pairs in the .2's. As I moved to charge testing, I found that my ES was high, always. 30-40fps. I did find a sweet spot that would produce accuracy in the .2's to .3's IF velocities happened to remain stable (3150fps) for that group. It would not consistently repeat due to ES/harmonics. I tested neck tension and changed primers to no avail. I even jammed bullets .010" just to see if it would help with ES. It got worse, up to 60fps ES. Round count on the barrel was now at 350. I initially attributed the high ES to the very slow powder...maybe not being completely burned.
I determined that I would just go back to my 245 Berger load. Having put 120 rounds down the tube in testing, I decided to take a measurement to the lands. This is where I started to see a problem. Throat growth appeared to be .050" over the last 150 rounds. A quick look with the bore camera confirmed my fears in that I could see almost no sign of the +P section of throat anymore. There may be .0001" of land depth left, but's it almost imaginary it's so faint.
I took it out with my RL33 245 Berger load and tested seating depth, it was still within .003" of optimal shooting producing .3 MOA. However, I lost 50fps. It took 1.1 grains to bring it back up to the normal speed/load but now I have ES in the 40fps range with RL33! Accuracy for now is still very good. This is an ELR gun for one mile plus shooting. Without ES inside of 10-12fps, I'm ****ing in the wind. Very frustrated trying to decide what to do now. I essentially have a "freebore" of 1 1/8" in this thing. I don't see how I could ever fix my ES problem with that going on.
My next step will be to take it to 2K and see what it does vertically. I may be surprised. The only fix I see is to have a smith chop off 1" plus of the shank and re-chamber with a traditional throat. So, my experience seems to align with Kirby's. Very disappointing. The hope was that the harder 400MOD barrel would actually prolong throat and barrel life.
Bob and Shawn Carlock re-barreled, chambered and +P throated and cerakoted my full custom Rem 700 300 RUM. The work was second to none and both Bob and Shawn were very personable and showed me around the shop when I picked up the rifle. I will very likely have them do more work for me in the future.
Barrel:
34" finished length Bartlein 5r 1:9 to 1:8 transitional twist 400MOD throated for 245 EOL Bergers.
Barrel break in didn't go so well, lots of copper that didn't seem to go away. After talking with both Bartlein and Shawn, I decided to stop cleaning and just go with it. Accuracy right off the bat was exceptional printing 5 side by side groups at 250 yards in the .1's to .2's MOA in load development. ES was typically around 20fps prior to barrel speed up. This was using RL33, ADG Brass and Fed 215M.
The barrel is typically cleaned down to bare metal and HBN coated every 50-70 rounds. I always keep a close eye out for a carbon ring and have not had an issue with that. I have never allowed more than 3 shots at a time (rare) and the barrel has never been hot. It is running some pressure.
Speed up finally happened at about 180 rounds where I backed my charge off by 1 grain to get back down to 3150fps with the 245. I attributed the poor break in and longer than normal speed up to the harder 400MOD barrel material. Accuracy was still very good and copper fouling was not causing any issues at this point. ES in this time frame was under 12 fps.
I did some testing with the 250 Atips (245 Bergers could not be found) and in my testing discovered that RL50 produced the absolute best velocity with the A-tips. I attempted to develop a load with the 250 and RL50. Initial results were great with 6 shots in pressure testing going into nearly the same hole at 100 yards. Seating depth testing at a low charge was producing pairs in the .2's. As I moved to charge testing, I found that my ES was high, always. 30-40fps. I did find a sweet spot that would produce accuracy in the .2's to .3's IF velocities happened to remain stable (3150fps) for that group. It would not consistently repeat due to ES/harmonics. I tested neck tension and changed primers to no avail. I even jammed bullets .010" just to see if it would help with ES. It got worse, up to 60fps ES. Round count on the barrel was now at 350. I initially attributed the high ES to the very slow powder...maybe not being completely burned.
I determined that I would just go back to my 245 Berger load. Having put 120 rounds down the tube in testing, I decided to take a measurement to the lands. This is where I started to see a problem. Throat growth appeared to be .050" over the last 150 rounds. A quick look with the bore camera confirmed my fears in that I could see almost no sign of the +P section of throat anymore. There may be .0001" of land depth left, but's it almost imaginary it's so faint.
I took it out with my RL33 245 Berger load and tested seating depth, it was still within .003" of optimal shooting producing .3 MOA. However, I lost 50fps. It took 1.1 grains to bring it back up to the normal speed/load but now I have ES in the 40fps range with RL33! Accuracy for now is still very good. This is an ELR gun for one mile plus shooting. Without ES inside of 10-12fps, I'm ****ing in the wind. Very frustrated trying to decide what to do now. I essentially have a "freebore" of 1 1/8" in this thing. I don't see how I could ever fix my ES problem with that going on.
My next step will be to take it to 2K and see what it does vertically. I may be surprised. The only fix I see is to have a smith chop off 1" plus of the shank and re-chamber with a traditional throat. So, my experience seems to align with Kirby's. Very disappointing. The hope was that the harder 400MOD barrel would actually prolong throat and barrel life.
Thank you for this .
It seems we all would like more speed, better groups ect. But at what cost ??
My thoughts on the extended throat and the +P to my 338 barrel would be just for hunting ..so at this point the barrel wear wouldn't bother me to much. I'm not going to set at the bench and bang away ..
This gives me something to think about .
Again thanks for posting this !
Rum Man
Kirby knows what he's talking about for sure.
waveslayer
Well-Known Member
I believe I already commented on this but Frank Green the owner of Bartlien barrels is not a fan of +P throats... he goes into detail over it and says it can very dangerous because of the pressures.
I can post the link if anyone wants
I can post the link if anyone wants
Tumbleweed
Well-Known Member
I'd be interested to see what he has to say because the +P does not cause a chamber to run at any higher pressures than SAAMI. The opposite actually and in our loading we bring it back up to a safe max SAAMI pressure. I see no way it could be considered dangerous
waveslayer
Well-Known Member
That's what I assumed, his question was and mine as well, where's the pressure testing/results? I'll grab the link once I hit my computer
Once it is determined that the useful +P throat life is gone, why could you not just cut the barrel
and re-chamber ?
Am I missing something ?
The OD of the breech end of the barrel of course needs to be big enough.
I am ordering one barrel that will have a 1.350"OD for 12 inches.
and re-chamber ?
Am I missing something ?
The OD of the breech end of the barrel of course needs to be big enough.
I am ordering one barrel that will have a 1.350"OD for 12 inches.
Tumbleweed
Well-Known Member
I have a little more testing to do to see how my vertical is at 2000 yards. If I'm not happy with what it's doing, then as I stated above, I may try to rechamber. This time with a conventional throat
It's not even +p as it really doesn't have the ability for extra pressure! He at least touched on the free bore on how it's NOT like it as extra or excessive free bore. When he states that you'll lose velocity from your existing load after "+P" is done is ridiculous, unless it's loosing pressure due to gas venting passed/in front of the bullet before making contact with original bore (the none +p area). Marketing 101 I guess!
I haven't read past the 1st page and most likely won't.
I haven't read past the 1st page and most likely won't.
bigngreen
Well-Known Member
I've used the +P type throating in chamberings that were mild to begin with to allow a step up in velocity while retaining some barrel life. 100% of the RUM and Lapua class cases I've seen with the +P were done extremely fast. When you think about it why do you need an extra 100 fps on the most aggressive chamberings any way, you only see 50-100 yards of gain on the extreme other end before going transonic, not worth it!!
