AR-Comp and Speer 120 gr Gold Dot

[mtnlvr]

What's the deal with the lack of consistent or even just published data on the Speer 120 gr 6.5 Grendel Gold Dot and AR-Comp?

I've spend a lot of time searching and reading various posts and it seems there really are no published sources that include this combo aside from Speer, which the consensus says that their data is very conservative. Their max is with AR-Comp is 25.3 gr as shown in the data below.

Source Bullet Powder Max Charge Max Vel
Speer 120 gr Gold Dot AR-Comp 25.3 2418
Speer 140 gr Spitzer SP AR-Comp 24.4C 2230
Speer 120 gr Gold Dot IMR 8208 XBR 25.4 2405
Hodgdon 120 gr TSX IMR 8208 XBR 28.0C 2419

Is it really that feasible for the same length (24") but different manufacturer barrel to be that different in what I'll call efficiency?

Or is it really that the Gold Dot bullet is that efficient?

And how can a 20 gr heavier bullet use the same powder charge?

Seems odd when you look at the 6.8 Rem SPC Data from the same two sources which essentially show very similar max charge values.
Source Bullet Powder Max Charge Max Vel
Speer 115 gr Gold Dot Benchmark 28.7 2628
Hodgdon 115 gr Sie HPBT Benchmark 28.5C 2581

Or 6.5 Creedmore.
Source Bullet Powder Max Charge Max Vel
Speer 140 gr Gold Dot IMR 4831 43.1C 2679
Hodgdon 140 gr A-Max IMR 4831 42.4 2720

It seems that with other powders and cartridges, Speer's Data more or less seems in line with other manufacturer's published data.

Sorry for the rant.

At any rate, I realize that every firearm and barrel are different, but what is a more realistic max charge of AR-Comp with the 120 gr Gold Dot?

I've seen people going to mid 27s and low 28s with 120 gr class bullets.
AR Comp 120 grain Speer Gold Dots and 95 degrees of Texas Heat
"Max" load for AR Comp and 123s

For reference, from my 12" PSA nitrided upper:
Factory 123 gr ELD-M Hornady Black ran at 2150 fps
123 gr ELD-M with 28.2 gr XBR ran at 2270 fps
123 gr SST with 28.2 gr XBR also ran at 2260 fps
123 gr SST with 31.0 gr CFE223 ran at 2160 fps
120 gr Gold Dot with 26.5 gr AR-Comp ran at 2071 and ~1MOA
120 gr Gold Dot with 27.1 gr AR-Comp ran at 2123 and ~2MOA

With the 27.1 gr of AR-Comp and the Gold Dot, from the looks of my brass, I've got room to explore, so that's what I plan to do. I'd like to see if I can find the next accuracy node within ~.5 more grains.

[A5BLASTER]

What's the deal with the lack of consistent or even just published data on the Speer 120 gr 6.5 Grendel Gold Dot and AR-Comp?

I've spend a lot of time searching and reading various posts and it seems there really are no published sources that include this combo aside from Speer, which the consensus says that their data is very conservative. Their max is with AR-Comp is 25.3 gr as shown in the data below.

Source Bullet Powder Max Charge Max Vel
Speer 120 gr Gold Dot AR-Comp 25.3 2418
Speer 140 gr Spitzer SP AR-Comp 25.4C 2230
Speer 120 gr Gold Dot IMR 8208 XBR 25.4 2405
Hodgdon 120 gr TSX IMR 8208 XBR 28.0C 2419

Is it really that feasible for the same length (24") but different manufacturer barrel to be that different in what I'll call efficiency?

Or is it really that the Gold Dot bullet is that efficient?

And how can a 20 gr heavier bullet use the same powder charge?

Seems odd when you look at the 6.8 Rem SPC Data from the same two sources which essentially show very similar max charge values.
Source Bullet Powder Max Charge Max Vel
Speer 115 gr Gold Dot Benchmark 28.7 2628
Hodgdon 115 gr Sie HPBT Benchmark 28.5C 2581

Or 6.5 Creedmore.
Source Bullet Powder Max Charge Max Vel
Speer 140 gr Gold Dot IMR 4831 43.1C 2679
Hodgdon 140 gr A-Max IMR 4831 42.4 2720

It seems that with other powders and cartridges, Speer's Data more or less seems in line with other manufacturer's published data.

Sorry for the rant.

At any rate, I realize that every firearm and barrel are different, but what is a more realistic max charge of AR-Comp with the 120 gr Gold Dot?

I've seen people going to mid 27s and low 28s with 120 gr class bullets.
AR Comp 120 grain Speer Gold Dots and 95 degrees of Texas Heat
"Max" load for AR Comp and 123s

For reference, from my 12" PSA nitrided upper:
Factory 123 gr ELD-M Hornady Black ran at 2150 fps
123 gr ELD-M with 28.2 gr XBR ran at 2270 fps
123 gr SST with 28.2 gr XBR also ran at 2260 fps
123 gr SST with 31.0 gr CFE223 ran at 2160 fps
120 gr Gold Dot with 26.5 gr AR-Comp ran at 2071 and ~1MOA
120 gr Gold Dot with 27.1 gr AR-Comp ran at 2123 and ~2MOA

With the 27.1 gr of AR-Comp and the Gold Dot, from the looks of my brass, I've got room to explore, so that's what I plan to do. I'd like to see if I can find the next accuracy node within ~.5 more grains.

Looking for pressure signs on grendel brass will get you hurt.

It typically doesn't show up until your way past safe pressure.

Your better off watching the velocity on the graph and stop when you find the spike or dump in velocity.

As far as arcomp and the 120 gold dot I don't use them so can't offer any insist on them.

[Kswhitetails]

^^^^^^^^^^^^^^^^^^

This.

[VASCAR2]

There was another thread recently concerning the lack of 6.5 Grendel data for AR Comp. I have suggested everyone send an email requesting Alliant to test their powders with the 6.5 Grendel. Another option might be to get Sierra or Hornady to test AR Comp in the 6.5 Grendel with their 120 grain bullets. We are making headway, about five years ago I took a tour of the Sierra bullet factory. I asked the rep if they would ever test for the 6.5 Grendel. His response was he doubted it because they were running at 100% capacity and he didn’t anticipate many new products. I got the impression Sierra was not interested in following up on a cartridge pushed by a competitor, Hornady.

There has been a down turn in demand so it can’t hurt to ask for more 6.5 Grendel reloading data. Target Sports has seen a marked increase in 6.5 Grendel ammo sales in the last couple of years. Other than Alliant I figure Hornady, Sierra and Nosler would be apt to offer data on Alliant powders. Can’t hurt to ask them to test Alliant powders.

[mtnlvr]

There was another thread recently concerning the lack of 6.5 Grendel data for AR Comp. I have suggested everyone send an email requesting Alliant to test their powders with the 6.5 Grendel. Another option might be to get Sierra or Hornady to test AR Comp in the 6.5 Grendel with their 120 grain bullets. We are making headway, about five years ago I took a tour of the Sierra bullet factory. I asked the rep if they would ever test for the 6.5 Grendel. His response was he doubted it because they were running at 100% capacity and he didn?t anticipate many new products. I got the impression Sierra was not interested in following up on a cartridge pushed by a competitor, Hornady.

There has been a down turn in demand so it can?t hurt to ask for more 6.5 Grendel reloading data. Target Sports has seen a marked increase in 6.5 Grendel ammo sales in the last couple of years. Other than Alliant I figure Hornady, Sierra and Nosler would be apt to offer data on Alliant powders. Can?t hurt to ask them to test Alliant powders.

I did see that thread and I did send an email to Alliant asking for AR-Comp data. The response I received today...

"Alliant does not have the data, but Speer does. We are sister companies and use the same testing procedures and often times labs."

Looking for pressure signs on grendel brass will get you hurt.

It typically doesn't show up until your way past safe pressure.

Your better off watching the velocity on the graph and stop when you find the spike or dump in velocity.

As far as arcomp and the 120 gold dot I don't use them so can't offer any insist on them.

I definitely watch velocity. Here's the plot from my last outing. Velocity looks consistent, and although the SD's increased during the middle loads, it was back on the way down towards the higher end.

Annotation 2019-08-20 173334.jpg

I understand that brass condition alone is not reliable, and that's why none of us rely solely only that when we develop a load. Accuracy, point of impact shift, bolt force, velocity, brass condition, primer condition, recoil, sound, etc. We look at all of that during load development even if we may not stop to think about all of that. It's all weighed in, differently for each person, and each application. I personally don't like to ignore my brass. Watching how much the primers are flattening, while working up different loads and over different powders, etc., even though they are far from "flat", gives an idea of how fast you are progressing up the pressure scale albeit subjective.

Velocity however is objective, and some say, is king. I don't think I'd go that far, but I would like to find the next accuracy node above the charges that I've plotted above. From what I've seen so far out of my own barrel and the postings around here, aside from Speer's (cough...Alliant's) data, I see no reason to not proceed.

[Drillboss]

The sad fact is that Speer's published data is the only pressure tested data point for AR Comp that exists. You pointed out in the OP that "It seems that with other powders and cartridges, Speer's Data more or less seems in line with other manufacturer's published data." I see no reason not to believe that 25.3 grains of AR-Comp under the 120 gr Gold Dot is a max load.

Sierra released their data about the same time Speer did and there are 5 powders common between the two data sets for 120 grain bullets. Speer's loads are 0.5 to 2.5 grains lighter than Sierra's and they are 20 to 125 fps slower. There must be something about the construction of this Gold Dot bullet that results in higher pressures and lower velocities than for the Sierra bullets. I also noticed that Speer's 120 gr data shows very similar performance between AR-Comp and 8208XBR. Looking back to Sierra's data, 27.4 gr of 8208XBR is a max load. So maybe 27.4 gr would have been close to a max load for AR-Comp if Sierra had tested it with their 120 gr pills.

It would be great if some of the Pressure Trace and/or Quickload users out there could share some thoughts and opinions on AR-Comp.

By the way, check your data again for the Speer 140 gr data. I'm seeing 24.4 gr as their max load, not 25.3. Stay safe.

[mtnlvr]

The sad fact is that Speer's published data is the only pressure tested data point for AR Comp that exists. You pointed out in the OP that "It seems that with other powders and cartridges, Speer's Data more or less seems in line with other manufacturer's published data." I see no reason not to believe that 25.3 grains of AR-Comp under the 120 gr Gold Dot is a max load.

Sierra released their data about the same time Speer did and there are 5 powders common between the two data sets for 120 grain bullets. Speer's loads are 0.5 to 2.5 grains lighter than Sierra's and they are 20 to 125 fps slower. There must be something about the construction of this Gold Dot bullet that results in higher pressures and lower velocities than for the Sierra bullets. I also noticed that Speer's 120 gr data shows very similar performance between AR-Comp and 8208XBR. Looking back to Sierra's data, 27.4 gr of 8208XBR is a max load. So maybe 27.4 gr would have been close to a max load for AR-Comp if Sierra had tested it with their 120 gr pills.

It would be great if some of the Pressure Trace and/or Quickload users out there could share some thoughts and opinions on AR-Comp.

By the way, check your data again for the Speer 140 gr data. I'm seeing 24.4 gr as their max load, not 25.3. Stay safe.

Good catch of the 140 gr. Thanks for fact checking! I corrected it.

I did get another response back from Alliant saying "they load within a percentage of industry standards for Chamber pressures" and won't divulge what that is for good reason.

[Former Cav]

funny... I had just called up alliant two days ago asking for data on AR-Comp and 6.5 Grendel and they said they had none.
oh, and I have a chart from alexander arms that shows a 28.0 grain load with a 120 bullet.
I have 5 loads worked up to test for accuracy using a 123 sst .....27.0, 27.2, 27.4, 27.6 and 27.8 grains.
If I get a "sweet group"...meaning less then 1 inch, then I will bracket that load in .1 increments. Just like I used to do for my prairie dog loads. Will also chronograph it at that time.
will keep you posted.

[mtnlvr]

funny... I had just called up alliant two days ago asking for data on AR-Comp and 6.5 Grendel and they said they had none.
oh, and I have a chart from alexander arms that shows a 28.0 grain load with a 120 bullet.
I have 5 loads worked up to test for accuracy using a 123 sst .....27.0, 27.2, 27.4, 27.6 and 27.8 grains.
If I get a "sweet group"...meaning less then 1 inch, then I will bracket that load in .1 increments. Just like I used to do for my prairie dog loads. Will also chronograph it at that time.
will keep you posted.

Looking forward to your results. Please include your bbl length and action type.

I've got a continuation of my ladder loaded for my next outing starting at 27.3 going up to 27.9 in 0.2 gr steps. Not sure I will end up firing them all yet. This is for my 12" bbl AR. I'm hoping to get out this weekend.

[Drillboss]

funnjy... I had just called up alliant two days ago asking for data on AR-Comp and 6.5 Grendel and they said they had none.
oh, and I have a chart from alexander arms that shows a 28.0 grain load with a 120 bullet.
I have 5 loads worked up to test for accuracy using a 123 sst .....27.0, 27.2, 27.4, 27.6 and 27.8 grains.
If I get a "sweet group"...meaning less then 1 inch, then I will bracket that load in .1 increments. Just like I used to do for my prairie dog loads. Will also chronograph it at that time.
will keep you posted.

Cav, can post a copy or a link to that AA data. I can?t find AR-Comp in the reloading data on their website.

[BobinNC]

Not pressure tested but it is useful AR Comp data with the 120 gr Speer GD in an 18" barrel.

https://www.youtube.com/watch?v=vvx2F0G5GvY

Some more AR Comp data also non-pressure tested, but contains one or two loads.

http://press.starlinebrass.com/wp-content/uploads/2018/04/6-5-grendel-load-data.pdf

https://www.shootingtimes.com/editorial/handloading-allows-6-5mm-grendel-shine/99645

[Former Cav]

Drillboss,
go here

https://www.shootingtimes.com/editorial/handloading-allows-6-5mm-grendel-shine/99645

[Drillboss]

Drillboss,
go here
https://www.shootingtimes.com/editor...el-shine/99645

Sorry, that's just another guy saying "Here's what I did." Still not pressure tested. Call me a wimp, but I'm still waiting on pressure data before I dive in on web-based reloading info.

[FW Conch]

AR Comp is like My x wife. I can live happily ever after without either of them

[mtnlvr]

AR Comp is like My x wife. I can live happily ever after without either of them

Well come on... That needs further explanation. And I'm bot talking about the X-wife.

Why did you give up on AR-Comp? And what is doing its duties now?