It's already hit it's "potential". If you took the time to wade thru the previous 88 pages you'll find it has a pretty avid established following. As for the shortages recently all the reloading components have become available although you have to remain alert and act fast when things become available. When I could buy 5.56 ammo for 30 cents a round they were my favorite go to and I still have a pretty good supply but since discovering the Ham'r and not figuring the brass cost I can reload them for 42 cents a round so I think I found a new favorite. Not only are they more accurate (at least out to 150 yds) than the typical 5.56 but they are WAY more effective when they hit. Shoot a potato or melon with a 5.56 and a 300 Ham'r and you will become a believer!

I think what he means is like the 6.5 Grendel, which took nearly 15 years to achieve market acceptance. Albeit relatively slow, I think the difference between these two cartridge introductions is the 300HAMR roll-out is a function of unfortunate timing (pandemic/market panic), whereas the Grendel was a result of short-sighted business strategy. Alexander Arms used the Grendel's copyright / trademark to maintain a chokehold on every aspect (ammo, dies, barrels, etc) related to the cartridge. For like the first 5-10 years after its introduction, if you wanted a Grendel then you had to buy directly from Alexander Arms. Grendel is a great round... I probably never would have bought my first 300BO is it hadn't been for all the BS around the Grendel at that time.

300HAMR is not a "new" cartridge, not that there are many of those anymore, but rather a revision/evolution to several proven existing calibers (300 Whisper, 300 Blackout, 7.62x40mm). The hurdle to entry is fairly low and is a easy transition for shooters who are already shooting the 300BO and looking for a little more velocity. The Grendel was more of a "new" cartridge and market was unfamiliar with it. Yes, derivative of 6PPC, but unless your were shooting competitive benchrest then you wouldn't know anything about this cartridge.

To add to this, 300 HAM'R is easily adopted since it uses a standard .223/5.56 BCG and readily available magazines from respected manufacturers. The massive number of different grain and construction bullets that can be utilized gives it staying power too. I completely abandoned 6.8 when 300 HAM'R came out. No proprietary bolt or expensive Barrett magazines. Timing happened to be excellent for me because I had 2500 rounds of 6.8 Hornady 110gr BTHP I was able to sell for almost double what I paid due to the ammo shortage.

Great article on terminal performance for the HAM'R 150 Bonded in this month's shooting Illustrated.

Too many just take the energy level of the 5.56 for granted because it comes in the AR platform, and they forget about the old 30-30. However, Mr. Wilson often stated that the goal for the 300 HAM'R was to reach the power of the 30-30 and it looks like he did it!

For decades the old lever-action rifles were considered the ultimate American utility weapon, but that has been changing as the AR has grown in popularity. Now you can have the "modern" features of the AR and the additional energy levels of the 30-30.

To finish probably the most perfect statement about the HAM'R you may want to add the following & sell it as a trademark to WC.

". . . without any of the associated drawbacks of moving to a larger platform."

I am currently working on load development using 130 2007 Speer FNHC, 135 FTX and 150 Speer 2023. I to am struggling with flyers and can not seem to figure out why. I may either be trying to push them too fast using CFEBLK or I have too much jump. I believe some of the issue is jump. I am currently using D&H mags from WC and can not run anything over 2.245 overall length. Any recommended mags that will allow longer overall length would be greatly appreciated. If you know of some can you share details along with max overall length they allow?

Regarding flyers and my load development:

Using the Speer 2023 150 SPHC loaded at 2.245 with ogive to base of 1.653 I have a .144 jump to the lands. At 25.4 grs of CFEBLK (Avg 2265 fps) its shoots shotgun patterns at 5 plus inches. Using same 25.4 charge, If I remove the lead point to reduce jump to .090 I have shot on one occasion a .7" group but most are in the 1" - 1.25" which is a lot better. I could only find these 2023's and really only wanted to try them to see how they shoot. I do believe my barrel will shoo the heavier 150 grain projectiles better than 130 gr due to the fact I am not seeing the flyer issue as much with the 150 grain after reducing the jump.

With the 130 FNHC 2007 I have been able to reduce jump between .033 - .055 and with 28.2grs of Lot 17 CFEBLK (Avg 2500 fps) I have managed to get 1" groups if measured without counting the flyers. What is happening is I seem to get a good group going then I will have one or two shots open the group up to 1.5" / 2"s in just about every 5 shot string I shoot. When loading, I measure everything from the ogive and try to keep them within .001 tolerance and always trickle up by hand to the charge weight.

My 135 FTX is not going much better and suffer from the same flyer scenario.

My plans moving forward:
I am using LC 5.56 converted brass but do have some WC 300 Ham'r brass that I am going to try with the same loads to see if I have the same flyer issue.
I do have a backorder for the Speer 135 Bonded from WC and will try these once I have them.

I have also acquired some 125 TNT projectiles and the jump in my 16" Ranger profile with these projectiles is .128. Not sure how these are going to shoot. For some they seem to shoot pretty good.

I would be curious what loads everyone has settled on using these projectiles and if they have observed flyers?

I had the same issue as you with flyers until my barrel had around 200 rounds thru it, with most flyers being the 4th and 5th shots. I also discovered my scope ring screws somehow managed to come loose when the last group with flyers really opened up. I'm using Lancer mags and am running an overall length of 2.255 although they seem to run between 2.250 and 2.260 depending on the bullet I'm loading. The best groups I've ever gotten were with the 150gr Speer 2022 and second best with the 125 TNT.

You didn't mention how much load development you did. I started a little above min and worked my way up. With all the bullets I've loaded so far my barrel seems to like something around a grain less than max load and the difference is significant being covering a 5 shot group with a dime or a silver dollar. Since my shots will never exceed 150yds I'm not sweating the 50fps or so I'm losing to get better accuracy.

I'd also ask if you clean your barrel between strings. Until my barrel was broke in if I shot more than one 5 shot group they would progressively get worse...even with the same load.

I've got some 2023s but haven't got around to trying them (and probably never will) since I acquired some 2022s which are the most accurate I've found to date. I'm running the 2022 over 25gr of CFEBLK with CCI 450 primers and WC factory brass. My second best load is the TNT over 26.5gr CFEBLK with the same primers and brass.

Thanks Tx for your quick feedback. I believe you have hit it on the head on two major points.

I have between 150 - 200 rounds thru this barrel. I just acquired it in late November and started shooting it in December. I have cleaned it three times so far, but not after every range day. I run suppressed and was using AA1680 powder for a while and that is some dirty, smoky powder. I was also way over gassed so I did would have to clean the BCG every time I went out. I have an adjustable gas block now which appears to have solved the issue along with CFEBLK. I will do a better job at cleaning the barrel each time I shoot it and see if that helps. I bet it will.

My flyers are also 4th and 5th shots. I started load development shooting 3 shot groups to try and save resources and did not have many flyers at all. Lately I have been able to acquired additional supplies so I have moved to 5 shot groups to try and hone in on a load and that is when I really started noticing the flyers.

I am going to have to get some of these Lancer mags and try them. I am also thinking of modifying these D&H mags to see if I can get a few thousands additional clearance out of them.

My load development strategy was to start mid load and move up to max, again to try and mitigate using too many resources. I am using lot 17 of CFEBLK. I have only seen slightly flat primers but not that bad so I am limiting my load to the WC velocities they provided to keep everything in the safe zone. I also shoot the 6.5 Grendel and you really have to keep an eye on pressure signs with that platform so I am very sensitive to pressure. I was really surprised I have not experienced any type of smears or swipes at all with the 300 Ham'r.

Before continuing load finalization I am going to shoot more of the 125 TNT's since they are the cheapest rounds I have and get my round count up.

These projectiles may not be a jump sensitive as I thought if you are getting the 125 TNT to shoot. My jump is .128 at 2.245 COAL. Do you know what your jump is in your load that shoots?

So far my best shooting projectile is the Speer 150 2023 with the tip removed. My focus is hunting and so I believe my choice will be between the 135 FTX and 130 bonded hot core I have on backorder. I don't believe I am going to continue to work on the Speer 2023 since I have to mod them to get it to shoot.

I am currently running a Sig Whiskey 3 x 9 scope on it. It is OK, but I have an Athlon Aries 2.5x15 I have been thinking of moving over to it.

Respectfully, you're over thinking it.
This isn't ELR, bench rest or the like so diving that deep into measurements isn't likely what you need to be doing.
You are focusing on the minutia and your issue is entirely likely to be caused by something big you're walking right past.

There can be a dozen different gross deficiencies leading to your issue. Anything from case capacity variances on modified cases to rifle component and assembly issues. (early in the thread case capacity differences for conversion considerations are touched on)

I'd offer the recommendations to:
Load to magazine length. (I had no luck with DH 300BLK mags but have been content with Lancers & am now moving to MagPul 20rds to preserve even more brass life)
Use known quality brass & recommended powders and projectiles to develop loads.
If you can't group 1.5moa with 135-150gr or around 1moa with 110-125gr recommended projectiles I'd start digging into the rifle components & assembly.

There are probably less than a dozen users in the thread who've ever concerned themselves with measuring jump to dial a load in and entirely too many people posting tiny group pics don't even consider it. That would lead me to the ASSumption that 300HAM'R generally isn't going to need that sort of nitpickery to achieve results.

Hopefully you don't take this personally. I'm in no way trying to belittle you because I have felt that pain. I have had my share of frustration with a number of different rifles & I hope you can get it dealt with quickly.

There are a couple of potential reasons that you are getting flyers.

Barrel Getting Hot:
You mentioned that they occur on the 4th and 5th shots. If this is consistent then it points to the barrel getting a bit whippy as it gets hot. You might slow down your rate of fire to allow the barrel to cool off between shots and groups. Give this a try and see if it makes a difference. When I am shooting groups, I shoot 3 or 5 shot groups and allow 1 minute between shots. I let my barrel rest for 15-20 minutes between groups to allow it to return to ambient temperatures.... depending on temperatures this can go quicker in colder climates. If you are using a can then you have to keep in mind that the can is a giant heat sump. That is keeping the end of the barrel hot.... try taking it off between groups. Both the barrel and suppressor will cool off much faster.

The other possibility is Neck Tension:
> You are using converted brass LC brass. Even with the same headstamp the thickness of the case wall/neck may vary by year creating different neck tension. If you aren't sorting by year then you might consider doing this.
> You're using converted brass (unknown # firings???) so even with the same wall thickness the brass hardness may be different from case to case resulting in different neck tensions. This can be mitigated by annealing the necks on the newly formed HAMR cases.

Good luck with the reloading and the barrel break-in. For what it is worth, I have had rifles that took 100 rounds to smooth out and others that took 200, I have also had a very few that shot great after 20 rounds.
I also use Lancer mags and I have loaded rounds out to 2.25" OAL. I do know that WC considered OAL with each bullet as they worked out their load data. I have found no problem with using their info as a good starting point. Only after getting a good load showing the best combination of velocity and accuracy will I tweak seating depth.

I noticed that you seem to be trying a few bullets and working on more than one load at a time. I normally test one load at a time and give the rifle a good cleaning each time I change bullets. It is as if the barrel needs to be "seasoned" to whatever bullet I'm testing.
As you, in my early testing I shoot 3-shot groups and only switch over to 5-shot groups once I get really good results.

One really important factor that showed up in my testing is that not all bullets are not created equal. Pressure levels were highly different from one bullet type to the next EVEN if they were all the same weight. Consider the 125 grain bullets. I tried the Sierra Pro Hunters and got really good accuracy, the 125gr. TNT gave me so-so accuracy, and some pre-production 125 gr. Lehigh CC were the best thing yet. The crazy part is that the next barrel may just love the 125 TNT's.
What will make you want to pull your hair out is when you have more than one barrel and each one prefers a different load.

I have never measured the "jump" and really don't have the gear to do it. I figured Mr. Wilson done the heavy lifting with all the testing so I just load to his recommended OAL.

I would like to ask the group a question regarding barrel break in. In the old days there was a lot of stock placed in lapping a barrel...either with a patch soaked in JB bore paste or using bullets with varying levels of grit embedded on them. Does anyone still do that? I've had a couple rifles make a remarkable change in accuracy by smoothing out the barrel with lapping.

If I have a barrel that just isn't shooting as I think it should, I'll try some lapping with JB bore paste. But the barrels today are a good bit smoother than those made just a few decades ago. At the same time, I have never seen a little lapping hurt a barrel,

Top custom barrels (Krieger Bartlein, etc) don't require lapping, which is part of the +$400 barrel blank cost. There are some who use JB Paste and others who are using polishing compounds used by machinists for polishing engine heads. Also, there are bore lapping kits by Wheeler. More recently, David Tubb introduced a line of impregnated bullets and DIY compound kit to lap bores and for long-term bore maintenance. Apparently, he uses it all barrels and keeps setting shooting records.

I certainly appreciate all of the responses and take nothing personal. I have only been reloading for about 4 years so I still have a lot to learn. Few things that has been mention like trying to do multiple load developments at the same time. I am guilty of this and need to make some changes and see if this works.

I enjoy the data in understanding what the projectiles max OTB is to the lands. It is part safety and the other is I enjoy it. I'm a data type of person anyway. With the AR platform and limited by mags, very rarely or maybe ever, will you be able to hit the lands. I am not even a competent shooter much less Bench rest.. LoL. Regarding jump, I shoot the 6.5 Grendel and my best combination is the Nosler 129 ABLR and ARComp. I have easily shoot the best groups of my life with this combination and the jump is .145. Just about everything Nosler shoots well in all of my Grendels so I understand how the projectiles factor into the ability of shooting good groups. When looking at this platform I saw a lot of very good groups people have shared and I felt like this was going to be an easy development cycle. It still maybe but I have to learn the what it takes to make it work and what does not work for my setup. BTW, I can shoot 1.5 MOA easly with this setup but I guess the impression I had with the 300 Ham'r is making me think I can do better.

Regarding other recommendations:

Neck tension: I did see Mr Wilson's recommendation regarding reducing the expanding ball down to .305. Mine was closer to .307 before I polished it down. I only recently did this.
Using modified or converted brass: Moving forward, I am only going to use the WC brass for load development and see if it make a difference. Thanks for bringing this up, I was thinking the same thing but I have tested the LC vs WC brass and there pretty close.

Heat soaked barrel: I generally do not shoot fast groups when trying to develop a load. Based on my LabRadar it is generally around a minute between rounds and after I shoot a group, I will take the walk down to the target and let the barrel cool. I also have a modified computer fan setup I use for cooling, especially during summer months.

Regarding other variances: I do have another issue I have not brought up and that is with the bolt carrier group I purchased from Midway. As mentioned earlier, I did have an over gassing issue (1 o'clock brass ejection 95% of time) and AA1680 which is a bit smoky and dirty. After shooting 20 rounds or so the bolt is really dirty and becomes hard to move. After cleaning it works with no issues. I thought this bolt issue was due to 1680 and over-gassed, however, I'm not so sure now. I just added an adjustable gas block and got it dialed in. Fired another 20 rounds before coming home. When I took it apart today to clean it, it was better than before but it was still harder to move the bolt than I was expecting. Anyone else see this before? Not sure if this could be a factor or not. fired brass all looks exceptional.

Thanks to everyone who has responded. It is this type of support that makes a difference whether or not a platform is successful or not, a least from the shooters perspective.

I am going to use this 300 Ham'r for pig hunting as well as deer next year. Hopefully I can make a trip soon and shoot some pigs.

I brought my youngest daughter hunting this year and she got a shot at a doe and missed it. We've pig hunted together and she generally does pretty good. Missing was more my fault however. I told her, I generally take neck shots on deer and told her do what she feels comfortable with. It was cool morning and sun was over the tree's. Two doe came out 105 yards due west of us and the sun was shinning on them and made them look like they were glowing. It was awesome. We were hunting off the ground in a clump of trees shooting from a tripod. She tried to do a high neck / head shot and missed. It tore her up a pretty bad. She told me later she needed more trigger time.

I had my brand new 300 Ham'r in the truck so I took it and let her shoot it with some 110gr V-Max I was going to use for break in. After taking a few shots and a little instruction, she shot a clover leaf at 85 yards. She took the target to show everyone. I was proud of her.

Have you verified your Headspace with the BCG? I had an issue with an Aero Precision BCG, Swapped out for the Sharps Rifle Company XPB BCG with the DLC coating, its a tad bit expensive but the bolt and carrier are S7 Tool Steel and it fixed my Headspace. Also the DLC coating is superbly easy to clean.

Quick questions: looking to build a 300 HAM'R bolt rifle to go with my two HAM'R AR-15's. I will be using a Savage 110 action. I have found a few places that offer Savage small shank barrels chambered in the 300 HAM'R, but I would appreciate recommendations from anyone that has gone down this road already. Second I noticed in the Ruger American conversion kit that a HAM'R Go-gauge was included. That Go-gauge appears to have been made by PTG. I could not find it listed for sale on either PTG's or WC's websites. Anybody know when or if this might become a standalone item for sale?

I called PTG and ordered them from a salesman over the phone. They make them to order. $80 for the pair (go and no-go). I did the RAR WC conversion and love it.....

Excellent, great to know. I noticed PTG offers two different chamber reamers...curious what the difference is. I'm going to guess slight tweaking of the throat dimensions.

I'll reach out to WC tomorrow to see if they have any extra laying around that they might sell me before ordering direct from PTG. I try to avoid ordering direct from PTG based on previous (very bad) experiences.

FYI: We chamber our barrels with PT&G reamer #12620 which matches the latest SAAMI spec not yet published

[/quote]FYI: We chamber our barrels with PT&G reamer #12620 which matches the latest SAAMI spec not yet published[/quote]


That begs the question is there a previous SAAMI standard that your older barrels were chambered for or does the latest standard apply to all WC barrels past and present?

FYI: We chamber our barrels with PT&G reamer #12620 which matches the latest SAAMI spec not yet published[/quote]


That begs the question is there a previous SAAMI standard that your older barrels were chambered for or does the latest standard apply to all WC barrels past and present?[/quote]

The "original" chamber and what is still shown on the SAAMI web site had a 45 degree angle leading into the rifling, with brand new barrels (less than 200rds through them) we occasionally experienced copper ring shaving from thin jacket bullets (125gr Sierra PH, 125gr Speer TNT, 130gr Speer HP and 135gr Hornady FTX). We changed this angle to 30 degrees which eliminated this problem and SAAMI approved this change at the Jan meeting a couple of weeks ago. All barrels WC has mfg in the past 14 months have this 30 degree angle. Older 45 degree angle barrels kind of fix themselves as they get 100-200rds through them and the sharp edge is slightly eroded. We didn't run into this "ringing" issue with any other bullets other than the ones listed above. The Speer 130gr HP was the worst offender and this is the reason we stopped selling that load. No other changes have been made to the chamber since day 1.

Bill, thanks for that detailed explanation regarding the revised chamber specs. My guns have coughed up several of the copper rings that you mentioned and, looking at the SAAMI chamber diagram, I would never have guessed the cause. I have two of the older 1-15 twist barrels and two of the newer 1-13 barrels.

One thing I noticed with the older barrels was that I needed adjustable gas blocks for reliability, whereas the newer barrels, even with their shorter mid-length gas systems, seem good to go. I would be curious to hear about that evolution.

When we developed the 95gr Controlled Chaos load using SOCOM powder we ran into full function issues with the intermediate length gas, so we decided to switch to mid gas so the guns would run under any circumstances. I really don't think you can over gas the guns to the point of malfunction, even with wide open ports. They just aren't finicky about gas like the Creedmoor's are.